There are currently multiple parallel and overlapping non-international armed conflicts taking place in Yemen, most notably between the government and the Houthis; the government and al-Qaeda in the Arabian Peninsula; as well as between a number of armed groups. The government is supported by an international coalition led by Saudi Arabia and the United States.
Multiple parallel and overlapping non-international armed conflicts are taking place in Yemen.
- First, the longstanding non-international armed conflict between the government, supported by southern separatists, and the Houthis continues.
- Second, the government is involved in a non-international armed conflict with al-Qaeda in the Arabian Peninsula.
- Upon invitation of Yemen’s President Hadi, an international coalition led by Saudi Arabia has intervened in favour of the government since March 2015. The involvement of Saudi Arabia and its allies does not affect the classification as it takes place with the consent of Yemen.
- Finally, a number of armed groups, including the Houthis and al-Qaeda in the Arabian Peninsula, are fighting each other. After the breakdown of their alliance in December 2017 the Houthis are also fighting the forces allied with former President.
In addition to the long-standing armed conflict opposing the Houthis to the government, new conflicts have emerged over the past years.
Two criteria need to be assessed in order to answer the question whether a situation of armed violence amounts to a non-international armed conflict.
- First, the level of armed violence must reach a certain degree of intensity that goes beyond internal disturbances and tensions.
- Second, in every non-international armed conflict, at least one side to the conflict must be a non-state armed group which must exhibit a certain level of organization in order to qualify as a party to the non-international armed conflict. Government forces are presumed to satisfy the criteria of organization. For further information, see 'non-international armed conflict' in our classification section.
Internsity of violence
Various indicative factors are used to assess whether a given situation has met the required intensity threshold, such as the number, duration, and intensity of individual confrontations; the types of weapons and military equipment used; the number of persons and types of forces participating in the fighting; the number of casualties; the extent of material destruction; the number of civilians fleeing; and the involvement of the United Nations Security Council. For further information, see 'non-international armed conflict - intensity of violence' in our classification section.
Outbreak of the conflict
From January 2011 onwards, against the background of the Arab spring, peaceful protests started to spread across the country to request the resignation of then President Saleh. The Houthis and tribal leaders supported the protests. After dozens of protestors were reportedly killed and many more injured during a demonstration in Sana’a on 18 March 2013, President Saleh declared a state of emergency. The violence further escalated towards the end of May when fierce fighting erupted between forces loyal to the President and tribal forces in Sana'a. Artillery caused heavy damage and thousands fled the city. Reportedly, the Yemeni airforce bombed armed groups around the capital and in the south. The escalating violence was not limited to the capital: Houthis seized more territory in the north and Islamist groups assumed control over several towns in the south. Thousands fled the violence in the south. Report of the United Nations High Commissioner for Human Rights on the Visit by the Office of the High Commissioner for Human Rights in Yemen, UN doc A/HRC/18/21, 16 September 2011. UNHCR, Yemen Clashes Kill two Refugees and Displace Thousands, 3 June 2011. In light of frequency and intensity of the armed clashes between government and anti-government forces and the number of people forced to flee, the intensity requirement was reached at the end of May 2011, possibly even earlier in the south of Yemen where government forces had been fighting al-Qaida in the Arabian Peninsula. For a detailed assessment looking at the various fronts in the escalating armed violence, see S. Haddad, ‘Yemen’, in L. Arimatsu and M. Choudhury (eds), The Legal Classification of the Armed Conflicts in Syria, Yemen and Libya, Chatham House, 2014, pp 28-30.
Armed clashes continued during the summer in various parts of Yemen. After expressing concern over the worsening humanitarian situations in Yemen in June, August, and September 2011, the Security Council adopted resolution 2014 (2011) in October 2011 to call on all parties to sign the transition initiative brokered by the Gulf Cooperation Council. After President Saleh signed the transition initiative, President Hadi was elected in February 2012.
The levels of armed violence remained significant between 2012 and 2014, in particular in the south where government forces attempted to drive out al-Qaeda in the Arabian Peninsula. In the north, fighting between the Houthis and tribal groups continued. See also S. Arraf, 'The Armed Conflict in Yemen: A Complicated Mosaic', The War Report 2017, Geneva Academy, October 2017; Stuart Casey-Maslen (ed), The War Report 2012, Oxford University Press, 2013, p 188.; Stuart Casey-Maslen (ed), The War Report 2013, Oxford Universtiy Press, 2014 and A. Bellal (ed), The War Report 2014, Oxford University Press, 2015, p 240 ff. The conflict reached a new phase with the seizure of the capital Sana'a by the Houthis in September 2014.
Seizure of Sana'a by the Houthis
Supported by forces allied with former President Saleh, the Houthis significantly extended their control over territory in Yemen and reached the capital Sana’a by September 2014. ‘Yemen: Houthi Rebels and Militia Clash in Sanaa’, BBC, 19 September 2014; M. Ghobari, ‘Houthis Tighten Grip on Yemen Capital After Swift Capture, Power-Sharing Deal', Reuters, 22 September 2014.
They assumed control over the government institutions in the capital and other areas under their control. In August 2016, they formalised their alliance with the Saleh forces and set up a joint governing body, which in turn further consolidated their de facto control over government institutions. However, the two groups remained separate in terms of their command and control structure. For more details on the control exercised by the Houthis and the Houthi Saleh alliance, see Final Report of the Panel of Experts on Yemen, UN doc S/2017/81, 31 January 2017, §§14 ff; see also S. Arraf, 'The Armed Conflict in Yemen: A Complicated Mosaic', The War Report 2017, Geneva Academy, October 2017.
Break-down of the Houthi Saleh Alliance in December 2017
Tensions between the Houthis and Saleh forces increased during autumn 2017. 'Yemen's Saleh Stages Mass Rally Amid Houthi Rift', Al Jazeera, 24 August 2017; G. Gasmin, 'Yemen: Is Saleh's Alliance With the Houthis Breakable', Al Jazeera, 21 September 2017. In late November 2017, clashes between Houthi and Saleh forces erupted in Sana'a, and former President Saleh announced the end of their alliance. 'Yemen War: Fighting Breaks Out Among Allied Rebels', BBC, 30 November 2017; F. Edroos, 'How Did Yemen's Houthi-Saleh Alliance Collapse', Al Jazeera, 4 December 2017. The fighting caused more than 200 casualties. 'Toll in Sanaa Fighting Rises to 234 Killed, 400 Wounded: ICRC', Reuters, 5 December 2017. After Houthi forces killed former President Saleh on December 4, the Houthis assumed exclusive control over the capital. P. Wintour, 'Yemen Houthi Rebels Kill Former President Ali Abdullah Saleh', The Guardian, 4 December 2017; S. Almosawa and B. Hubbard, 'Yemen's Ex President Killed as Mayhem Convulses Capital', The New York Times, 4 December 2017; N. Al-Maghafi, 'Rebel Infighting Leaves Yemen's Capital More Divided Than Ever', BBC, 14 December 2017; S. Kamali Dehghan, 'Houthis Detain Journalists Linked to Saleh as Airstrikes Intensify Over Yemen', The Guardian, 6 December 2017; 'Yemen: Ex-President Ali Abdullah Saleh Killed', Al Jazeera, 10 December 2017.
Since then, they constantly controlled the northern and western parts of the country by themselves whilst they were driven out of the southern governorates of Aden and Lahj shortly after the seizing Aden in the spring of 2015 by southern and coalition forces. ‘Yemen – Who controls what’, Al-Jazeera, 16 January 2019; ‘Saudi-backed Yemen forces take Aden from Houthis: residents’, Reuters, 15 July 2015. The forces allied with Saleh and his General People’s Congress Party have largely dispersed after the assassination of Saleh. They are internally divided and do no longer engage in significant military operations; thus, they are not a party of their own to the conflict. This is also indicated by their omission in the UN mediated peace talks in which they had previously been included. A. Alley, ‘Collapse of the Houthi-Saleh alliance and the future of Yemen’s war‘, POMEPS Studies 29 “Politics, Governance, and Reconstruction in Yemen”’, January 2018; International Crisis Group, ‘Is the Yemen Peace Process Coming back to Life?’, 7 September 2018.
Fighting between government forces and the Southern Movement/Southern Transitional Council
Since fleeing the capital after the Houthi take over, the Hadi government has been based in Aden and formed a tenuous alliance with the Southern Movement, a separatist group that emerged in 2007. Fighters of southern militias played an important part alongside the international coalition’s forces in pushing the Houthis out of the governorates of Aden and Lahj in the south of the country. R. Forster, ‘The Southern Transitional Council: Implications for Yemen’s Peace Process’, Middle East Policy Council, Fall 2017.
During 2017, the frictions between the Southern Movement and the Hadi government increased with the Southern Movement forming the Southern Transitional Council in Spring 2017. R. Foster, The Southern Transitional Council: Implications for Yemen's Peace Process, Middle East Policy Council, restricted access. After the Southern Transitional Council's ultimatum to President Hadi to dismiss the cabinet passed, armed clashes erupted in Aden on January 28. After two days of fighting, causing over 30 casualties, See UN Office for the Coordination of Humanitarian Affairs, Yemen: Escalation of Armed Clashes in Aden. Flash Update 2, 30 January 2018; 'Yemen War: Deadly Infighting Rages in Aden', BBC, 29 January 2018; 'O. Bin Javid, 'Fighting Intensifies in Yemen's Aden After Separatist Coup', Al Jazeera, 29 January 2018; P. Wintour, 'Yemen Separatists Surround Presidential Palace in Aden', The Guardian, 30 January 2018. the Southern Transitional Council / Southern movement announced that they had captured Aden and the Hadi government was confined to the Palace. M. Mukshashaf, 'Yement Separatists Capture Aden, Government Confined to Palace - Residents', Al Jazeera, 30 January 2018; B. Riedel, 'Advancing Separatists Could Restore South Yemen', AL-Monitor, 1 February 2018; A. Al-Mujahed and S. Raghavan, 'Yemen's War is so Out of Control, Allies Are Turning on One Another', The Washington Post, 3 February 2018. Depending on how the situation evolves, a new front could emerge in the armed conflicts in Yemen.
The fighting between forces loyal to the Hadi government and the Southern Transitional Council / Southern Movement brought to the forefront divergences between different members of the Saudi-led coalition: Saudi Arabia supports the Hadi government while the United Arab Emirates back the Southern Transitional Council / Southern Movement. Clashes between the two parties continue throughout 2018 and are not likely to be resolved in the course of the UN brokered peace process that mainly engages the Houthis and the Saudi led coalition with their “home territories”/areas of control in the North of Yemen. International Crisis Group, ‘Crisis Group Yemen Update’, 22 February 2019.
Development of the conflict
The intensity of the conflict has reached worrisome extents as necessary food and goods supply for the livelihood of the population have become so scarce that a major part of the people face the risk of starvation, especially if the fighting in Hodeidah, the country’s vital port for goods import, continues to cut off the supply chains to the regions inland. International Crisis Group, ‘How to halt Yemen’s Slide into famine?’, 21 November 2018; R. Gramer/C. Lynch, ‘U.N. body declares famine conditions in parts of Yemen’, Foreign Policy, 05 December 2018.
The humanitarian assistance of the World Food Programme has also become increasingly difficult as the access to the Red Sea Mills is blocked, where the organization stores a significant share of its grain supply for the country. M. Lowcock, ‘Statement on the Situation in Yemen’, 07 February 2019. The conflict has forced millions of civilians out of their homes. M. Lowcock, ‘Briefing to the Security Council on the humanitarian situation in Yemen’, 19 February 2019.
However, in December 2018 first steps towards a seizure of hostilities were taken within the frame of UN-mediated negotiations in Rimbo, Sweden; representatives of the Hadi government and the Houthi group agreed on an unconditional prisoner exchange as well as local ceasefires in major Yemeni ports as well as the redeployment of troops from the vital supply point of Hodeidah city. The implementation is to be overseen by a UN chaired redeployment coordination committee that leads a 75 staff members strong UN mission to help implementing and monitoring the agreement reached in Sweden. See Stockholm Agreement, 13 December 2018. See also P. Wintour, ‘Yemen peace talks: UN says Hodeidah should be under joint control’, The Guardian, 10 December 2018; L. Doucet, ‘Shaky truce in key Yemeni port of Hudaydah’, BBC, 28 January 2019. Yet, the parties disagree over the practical interpretation of the agreement and multiple breaches of the ceasefires have been reported. While the overall intensity of fighting has gone down in Hodeidah governorate it flared up in other sites across the country and the Yemeni-Saudi-border. Yemen Data Project, ‘Yemen Data Project Air Raids Summary January 2019’, February 2019; International Crisis Group, ‘Crisis Group Yemen Update no. 5’, 22 February 2019; ‘Aid group warns Yemen truce ‘on verge of collapsing’, Al Jazeera, 30 January 2019.
A series of indicative factors are used to assess whether armed groups exhibit to required degree of organization, such as the existence of a command structure and disciplinary rules and mechanisms, the ability to procure, transport, and distribute arms, the ability to plan, coordinate and carry out military operations, the ability to negotiate and conclude agreements, e.g. cease fire or peace agreements. If the criterion of a minimum organization of the armed groups is not fulfilled, there is no armed conflict. For further information, see 'non-international armed conflict - organization' in our classification section.
There are multiple armed groups and tribal militia active in Yemen. For most, there is not enough information available to analyse their degree of organization. However, among the key armed groups, both the Houthis and al-Qaeda in the Arabian Peninsula undoubtedly have a sufficient degree of organization. Apart from its leadership figures, little is known about the Houthis, but they control significant parts of territory in Yemen, including the capital since September 2014. This indicates that they are sufficiently organized to sustain military operations over a long period of time and to act as de facto authorities. S. Al Batati, ‘Who are the Houthis in Yemen’?, Al Jazeera, 20 March 2015.
The Houthis are a Zaidi Shia movement that emerged from the ‘Believing Youth’ movement which was founded by Hussein Badr al-Din al-Houthi in the late 1990s. Being rooted in the northern highland region of Yemen the initially peaceful movement started opposing the government of then president Saleh in 2004. Counter Extremism Project, ‘Houthis’; European Council on Foreign Relations, ‘Mapping the Yemen Conflict’, February 2017. Following several violent clashes in the subsequent years and their participation in the nationwide 2011 protests, the Houthis seized control over the capital Sanaa. They further expanded their territorial control to the South and West of the country to the area they currently control. ‘Yemen – Who controls what’, Al Jazeera, 16 January 2019; ‘Who are the Houthis in Yemen’, Al Jazeera, 29 March 2015. The group is led by several members of the Houthi family; Abdul-Malik al Houthi succeeded his brother Hussein Badr al-Din al-Houthi as the movement-leader after the latter’s assassination by government forces in 2004. Their aims in the conflict are not entirely clear but have traditionally been in the lines of political and territorial control as well as improving their economic situation. ‘Who are the Houthis and why are they fighting the Saudi coalition in Yemen?’, The Guardian, 21 November 2018. Despite heavy air bombing by the international coalition and a weapons embargo imposed by the United Nations Security Council, the Houthi forces managed to hold onto a significant share of the Yemeni territory since 2015. Stockholm International Peace Research Institute, ‘Arms Embargos, Yemen’, 2018; Yemen Data Project, ‘Yemen Data Project Air Raids Summary January 2019’, February 2019; International Crisis Group, ‘Yemen: Averting a Destructive Battle for Hodeidah’, 11 June 2018. Moreover they uphold cooperative relationships with Iran that supports the movement financially and allegedly with military training as well as weapons. ‘Who are the Houthis and why are they fighting the Saudi coalition in Yemen?’, The Guardian, 21 November 2018. The Houthis exercise de facto authority in the areas they control, detain large numbers of individuals and are sufficiently organized to have spokespeople representing the whole movement that took part in the negotiations with the Hadi government in Sweden. International Crisis Group, ‘Yemen: Averting a Destructive Battle for Hodeidah’, 11 June 2018; M. Griffiths, ‘Briefing of the Special Envoy for Yemen to the Security Council’, 19 February 2019. This indicates that they meet the organization threshold for non state armed groups in non-international armed conflicts.
Al-Qaeda in the Arabian Peninsula
Al-Qaeda in the Arabian Peninsula was formed by the merger of the Yemeni and Saudi branches of al-Qaeda in 2009. In 2011, an offshoot of the group, Ansar al-Shari’a seized control over large areas in the south, declaring them ‘Emirates’. However, the exact relationship between Ansar al-Shari’a Yemen and al-Qaeda in the Arabian Peninsula remains murky. Many consider that the former is a simply a naming exercise in order to attract more local fighters. Stanford University, Mapping Militant Organisations: Al Qaeda in the Arabian Peninsula, 12 May 2015; S. Haddad, ‘Yemen’ in L. Arimatsu and M. Choudhury (eds), The Legal Classification of the Armed Conflicts in Syria, Yemen and Libya, Chatham House, 2014, p 26. Little information is available about al-Qaeda in the Arabian Peninsula. Yet, the group's ability to control territory in the south, and to sustain concerted military operations against government forces and Houthis, is evidence that the group exhibits the required degree of organization.
The group is currently led by Quasim al-Remy. Despite concerted efforts by the international coalition, especially the UAE, to drive them out of their southern Yemeni strongholds, the group still has a strong presence in the southern regions of the country and engages in violent clashes with government and Houthi forces. S. Jones et al., ‘The Evolution of the Salafi-Jihadist Threat. Current and future Challenges from the Islamic State, Al-Qaeda and other groups’, Center for Strategic and International Studies, November 2018; ‘Yemen – Who controls what’, Al Jazeera, 16 January 2019. The group's ability to control territory in the south, and to sustain concerted military operations against government forces and Houthis by using a range of weapons such as improvised explosive devices, mortars, surface-to-air and anti-tank missiles , indicates that the group exhibits the required degree of organization. S. Jones et al., ‘The Evolution of the Salafi-Jihadist Threat. Current and future Challenges from the Islamic State, Al-Qaeda and other groups’, Center for Strategic and International Studies, November 2018; P. Salisbury, ‘Yemen’s Southern Powder Keg’, Chatham House, March 2018.
Southern Separatist Forces
Since the unification of the formerly separated northern and southern Yemeni countries, tensions continued between northern Yemeni government elites and the southern parts of the country that felt bypassed in the development of the country. In May 2017 the Southern Transitional Council was established, a quasi-government claiming the independence of the South once again. S. Dahlgren, ‘Popular revolution advances towards state building in southern Yemen’, POMEPS Studies 29 ‘Politics, Governance, and Reconstruction in Yemen’, January 2018; Southern Transitional Council, ‘About us’, Website of the Southern Transitional Council. Even though the Council regularly emphasizes their peaceful intentions, its forces have started to violently engage with the Houthis and AQAP as well as governmental forces since southern groups withdrew their initial support from the Hadi government in early 2018. Following a considerable number of clashes in January 2018, the fighting between the government and southern forces has mostly halted but the tensions remain high. ‘Yemen crisis – Why is there a war?’, BBC, 18 December 2018. After successfully taking the control of Aden and Abjan districts from the Houthis in 2015, and following the incremental expulsion of AQAP of southern districts, the southern forces control large parts of what has formerly constituted the independent southern Yemeni country. P. Salisbury, ‘Yemen’s Southern Powder Keg’, Chatham House, March 2018; R. Forster, ‘The Southern Transitional Council: Implications for Yemen’s Peace Process’, Middle East Policy Council, Fall 2017.
The ability of the groups to conduct concerted fighting efforts, such as the offensive against AQAP in the southern city of Mukalla in April 2016, exercise territorial control and their ability to engage in a long term cooperation with the international coalition, especially UAE forces, indicates that they meet the organization requirements. The forces that are backed by the UAE can be roughly divided into two larger segments: the regions of Lahj, Aden and Abjan are under the general command of Munir Mahmoud al-Mahshali, but directly instructed by local leaders; whereas the Shabwa forces are under the command of Mohammed al-Qamishi and Hadramawt units are directed by Faraj Salemin al-Bahsani. P. Salisbury, ‘Yemen’s Southern Powder Keg’, Chatham House, March 2018.
International intervention against the Houthis
Purportedly put under House arrest following the Houthi take over of the capital, President Hadi resigned in January 2015. However, he rescinded his resignation after fleeing to Aden, the second largest city, in February 2015. ‘Yemen President Quits Amid Worsening Crisis’, Al Jazeera, 22 January 2015. M. Ghobari and M. Mukhashaf, ‘Yemen’s Hadi Flees to Aden and Says he is Still President’, Reuters, 21 February 2015. He fled the country in March 2015 after the Houthis advanced towards Aden. Since then, he has been living in Saudi Arabia before heading to the USA for medical treatment in 2018. ‘Yemen President Flees Country as Country’s Turmoil Worsens’, Associated Press, 25 March 2015; ‘Yemen's President Hadi heads to US for medical treatment’, Al-Jazeera, 3 September 2018.
The day after he fled the country, upon his request, an international coalition led by Saudi Arabia initiated airstrikes against Houthi rebels in Yemen. Saudi Arabia, Bahrain, Qatar, Kuwait, and the United Arab Emirates cite extensively from the letter sent by President Hadi in their joint letter to the Security Council, see Identical Letters Dated 26 March 2015 from the Permanent Representative of Qatar to the United Nations Addressed to the Secretary-General and the President of the Security Council, UN doc S/2015/217, 27 March 2015.
Due to the request by President Hadi, the intervention takes place with the consent of Yemen. Hence, it does not affect the classification of the conflict. For further information on the relevance of consent, see 'contemporary challenges - relevance of consent' in our classification section. The validity of the consent can be debated because the legitimacy of President Hadi is contested in Yemen. However, at the time of the request, he was considered competent to express the will of Yemen by the international community at large. For a thorough discussion, see M. Byrne, ‘Consent and the Use of Force: An Examination of “Intervention by Invitation” as a Basis for US Drone Strikes in Pakistan, Somalia and Yemen’ 3 Journal on the Use of force and International Law 1 (2016), 97 ff; T. Ruys and L. Ferro, ‘Weathering the Storm: Legality and Legal Implications of the Saudi-Led Military Intervention in Yemen’, 65 International and Comparative Law Quarterly 1 (2016), p 81 ff, restricted access; see also J. Aparac, 'Yémen? Vous avez dit crise humanitaire?', La Revue des Droits de l'Homme, Mars 2017. The United Nations Security Council 'reaffirmed its support for the legitimacy of the President of Yemen, Abdo Rabbo Mansour Hadi' in Security Council resolution 2216 (2015), adopted on 14 April 2015. With the exception of Syria and Iran who maintain embassies in Sana'a, the international community continues to engage with President Hadi as the legitimate government of Yemen. See Final Report of the Panel of Experts on Yemen, UN doc S/2017/81, 31 January 2017, §22.
Initially, airstrikes were launched by Saudi Arabia and the United Arab Emirates, with Kuwait, Bahrain, Qatar, Morocco, Sudan , Jordan and Egypt contributing aircraft. ‘Yemen Air Strikes: A Guide to the Countries Backing Saudi Arabia’, Associated Press, 10 April 2015. In late 2015, Saudi Arabia, Bahrain, Qatar, the United Arab Emirates, Sudan, Morocco and Egypt sent ground troops to Yemen. ‘Number of Saudi-led coalition troops in Yemen “rises to 10,000”’, Reuters, 8 September; S. Al-Batati and K. Fahim, ‘Foreign Ground Troops Join Yemen Fight’, The New York Times, 3 August 2015; . ‘Qatar Sends 1,000 Ground Troops to Yemen Conflict: Al Jazeera’, Reuters, 7 September 2015; ‘Sudan Sends Ground Troops to Yemen to Boost Saudi-led Coalition’, Reuters, 18 October 2015; ‘Egypt Sends Up to 800 Ground Troops to Yemen’s War – Egyptian Security Sources’, Reuters, 9 September 2015; ‘Morocco Sends Ground Troops to Fight in Yemen’, Gulf News, 5 December 2015. As a consequence of their intervention, these countries are parties to the conflict in Yemen. For further information on who is a party to the conflict, see 'contemporary challenges - who is a party?' in our classification section. For the military component of the international coalition, see also Final Report of the Panel of Experts on Yemen Pursuant to Security Council Resolution 2140 (2014), UN doc S/2017/81, footnote 18.
Accusing Qatar to support terrorism, Saudi Arabia, Bahrain, Egypt and the United Arab Emirates cut diplomatic ties and cut off air, land and sea trade with Qatar in June 2017. At the same time, Qatar was ejected from the coalition. As a consequence, Qatar is no longer a party to the conflict. 'Qatar Crisis Complicates Yemen Civil War', The Economist, 12 July 2017. While the measures taken by Saudi Arabia, Egypt and the United Arab Emirates are often referred to as a blockade, the measures taken do not amount to a blockade as this term is understood under international law, see J. Ku, 'Dear Secretary Tillerson (and The World Media): Qatar is NOT Under a "Blockade", Opinio Juris Blog, 10 June 2017.The infighting between the Southern Movement and the forces loyal to President Hadi also causes friction within the coalition as Saudi Arabia backs President Hadi while the United Arab Emirates support the Southern Movement. In 2019, Morocco suspended its support for the coalition and thus likewise is no longer a party to the conflict. ‘Morocco suspends participation in Saudi-led war in Yemen’, Al Jazeera, 8 February 2019; ‘Morocco re-evaluates role in Saudi-led Yemen war coalition’, The Washington Post, 7 February 2019.
The coalition led by Saudi Arabia is accused of systematic violations of international humanitarian law. See for example, Human Rights Watch, UN: Suspend Saudi Arabia From Human Rights, 29 June 2016. For example, its January 2016 report, the United Nations Panel of Experts on Yemen concluded that in some cases, the Saudi-led coalition violated the principle of distinction in a ‘widespread and systematic manner’. Final Report of the Panel of Experts on Yemen Pursuant to Security Council Resolution 2140 (2014), UN Doc S/2016/73, § 128. Against this background, the support of the United States, United Kingdom, and France to the Saudi-led coalition has received intense scrutiny, including the question whether their support makes them a party to the armed conflict against the Houthis. See for example B. Wille, ‘We Need to Know More About the US’s Role in Yemen’, Just Security Blog, 22 April 2016; R. Goodman, ‘If US and UK Have Joined the Fighting in Yemen, What’s Their Duty to Investigate Alleged Saudi War Crimes?’, Just Security Blog, 20 October 2016; N. Weizmann, 'Are the U.S. and U.K. Parties to the Saudi-Led Armed Conflict Against the Houthis in Yemen?' Just Security Blog, 22 September 2016. All three countries export weapons to Saudi Arabia and have officers present at the joint headquarters of the coalition, but in itself this does not suffice to consider them a party under the support based approach. For further information on the support based approach, see 'contemporary challenges - who is a party?' in our classification section. However, although the information provided is to some extent conflicting, the United States appears to provide the Saudi-led coalition with aerial refuelling for air strikes. 'Exclusive: As Saudis Bombed Yemen, U.S. Worried About Legal Blowback', Reuters, 10 October 2016; J. Borger, 'US Military Members Could be Prosecuted For War Crimes in Yemen', The Guardian, 3 November 2016; P. Stewart and W. Strobel, 'U.S. to Halt Some Arms Sales to Saudi, Citing Civilian Deaths in Yemen Campaign', Reuters, 3 December 2016; P. Stewart, 'U.S. Weighs Bigger Role in Yemen's War, Boosting Aid to Allies', Reuters, 27 March 2017. Under the support based approach, this makes them a party to the conflict. For an extensive analysis of the U.S. data on aerial fuelling, see S. Oakford, 'The U.S. Military Can't Keep Track of Which Missions It's Fueling in Yemen War', The Intercept, 18 September 2017.
International Intervention against al-Qaeda
Since 2009, the United States has conducted drone strikes and special missions ground raids against al-Qaeda in the Arabian Peninsula with the consent of the government of Yemen. This raises the question whether they became a party to the non-international armed conflict between the Yemeni government and al-Qaeda in the Arabian Peninsula. The United States claimed that their drone strikes targeted high-level operatives to further their own counter-terrorism objectivey and it 'was not working with the Yemeni government in terms of direct action or lethal action as part of that insurgency'. Transcript of John Brennan’s Remarks,'U.S. Policy Toward Yemen', Council on Foreign Relations, 2012. Yet, against the background of the insurgency in Yemen, the United States' drone strikes and the scope of their mission more generally broadened to include wider support to the government against the insurgency by al-Qaeda in the Aarabian Peninsula. For example, in May 2016, special forces supported Yemeni and United Arab Emirates troops to evict al-Qaeda in the Arabian Peninsula from the port city of Mukalla. 'US Military Admits Troops Are Operating Inside Yemen to Combat Al-Qaida', The Guardian, 6 May 2016. Hence, the United States is considered a party to the conflict. See D. Pearlstein, 'The Yemen War', Opinio Juris Blog, 18 July 2012; R. Chesney, 'Reactions to the ACLU Suit: There is Armed Conflict in Yemen, and the US Is Party to it', Lawfare Blog, 18 July 2012; R. Goodman, 'A New War? The U.S. Involvement in Yemen's Internal Armed Conflict', Just Security Blog, 28 October 2013; R. Goodman, 'Ongoing "Drone Strikes" in Yemen Raise Four Questions', Just Security Blog, 21 April 2014; R. Goodman, 'Are AQAP Domestic Insurgents Covered by the AUMF', Just Security Blog, 29 April 2014; R. Goodman, 'What's Missing in New York Times "Latest Version" of U.S. Military Role in Yemen', Just Security Blog, 12 May 2014. In 2017, the United States significantly increased its airstrikes against suspected al-Qaeda militants in the Arabian Peninsula and conducted over 20 airstrikes in 2018. E.Schmitt, 'United States Ramps Up Airstrikes Against Al Qaeda in Yemen', New York Times, 3 March 2017. The Bureau of Investigative Journalism recorded 6-12 US attacks in Yemen during 2016, compared to 127 airstrikes in 2017, see The Bureau of Investigative Journalism,Yemen: Reported US Covert Actions 2017, last consulted 30 January 2018; see also E. Schmitt and S. Al-Batati, 'The U.S. Has Pummeled Al Qaeda in Yemen. But the Threat Is Barely Dented', The New York Times, 30 December 2017.
The United Arab Emirates, which initially joined the Saudi-led coalition against the Houthis, has become more involved in fighting al-Qaeda in the Arabian Peninsula, including with ground forces and in cooperation with the United States. W. Maclean, N. Browning and Y. Bayoumy, 'Yemen Counter-Terrorism Mission Shows UAE Military Ambition', Reuters, 28 June 2016. Following a joint United States - United Arab Emirates raid that led to civilian deaths, Yemen appears to have withdrawn permission for United States ground operations in February 2017, but not aerial strikes. D.E. Sanger and E. Schmitt, 'Yemen Withdraws Permission for U.S. Antiterror Ground Missions', The New York Times, 7 February 2017; F. Solomon, 'Yemen Will Ban U.S. Ground Missions After Last Week's Deadly Raid, Report Says', Time, 8 February 2017. In August 2017, the United Arab Emirates and the United States supported a ground offensive of Yemeni troops against al-Qaeda militants in southern Yemen. S. Al-Batati, E. Schmitt, 'Thousands of Yemeni Forces Target Qaeda Stronghold', The New York Times, 6 August 2017.
The United Arab Emirates still confirm a strict stance of condemnation towards AQAP, however the decisiveness of their approach is contested in light of reports of drawing on the support of local AQAP-related groups for their fight against the Houthis. S. Al-Batati, E. Schmitt, 'Thousands of Yemeni Forces Target Qaeda Stronghold', The New York Times, 6 August 2017; J. Fenton-Harve, ‘Al Qaeda’s Future in War torn Yemen’, Carnegie Endowment for International Peace, 25 September 2018; ‘Saudi Arabia, UAE gave US arms to al-Qaeda-linked groups: Report’, Al Jazeera, 5 February 2019; ‘Washington's Gulf allies gave sophisticated American weapons to al Qaeda, says report’, The Independent, 5 February 2019.
Yemen is a party to the four 1949 Geneva Conventions. All parties to the conflict are bound by Article 3 common to the 1949 Geneva Conventions that provides for the minimum standard to be respected and requires humane treatment without adverse distinction of all persons not or no longer taking active parts in hostilities. It prohibits murder, mutilation, torture, cruel, inhuman and degrading treatment, hostage taking and unfair trials.
Yemen is also a party to the 1977 Additional Protocol II applicable to non-international armed conflicts. The ability of the Houthis and al-Qaeda of the Arabian Peninsula to exercise territorial control over large parts of Yemen suggests that they fulfil the required criterion for the applicability of Protocol II, namely the ability to carry out sustained and concerted military operations; impose discipline; and the ability to implement Protocol II. In this sense, see also S. Haddad, ‘Yemen’ in L. Arimatsu and M. Choudhury (eds), The Legal Classification of the Armed Conflicts in Syria, Yemen and Libya, Chatham House, 2014, p 30. However, Protocol II does not apply between armed groups. All parties are bound by customary international humanitarian law applicable to non-international armed conflicts. Customary international law consists of unwritten rules that come from a general practice accepted as law. Based on an extensive study, the International Committee of the Red Cross maintains a database on customary international humanitarian law.
In addition to international humanitarian law, international human rights law continues to apply during times of armed conflict. Under human rights law, the territorial state has an obligation to prevent and to investigate alleged violations, including by non-state actors. Non-state armed groups are increasingly considered to be bound by international human rights law if they exercise de facto control over some areas.
A myriad of armed groups are active in Yemen. Below is a selection of the key armed groups. For a more detailed overview of other armed groups, see S. Haddad, ‘Yemen’ in L. Arimatsu and M. Choudhury (eds), The Legal Classification of the Armed Conflicts in Syria, Yemen and Libya, Chatham House, 2014, p 25-26; Mapping the Yemen Conflict, European Council on Foreign Relations, 2016. Alliances between the armed groups are fluid and frequently shifting.
- Houthi: The Houthi rebels are a Shia insurgency group that has been embroiled in a non-international armed conflict with government forces since 2004. The group aligned itself with the protests against the government in 2011 and seized the opportunity to extend its control over large swaths of territory in the north. Since September 2014, they have been in control of Sana’a, the capital of Yemen.
- Saleh forces: Forces loyal to former President Saleh allied themselves with the Houthis and formalised their alliance in August 2016. However, in December 2017, their alliance broke down.
- Al-Qaeda in the Arabian Peninsula /Ansar al-Shari’a in Yemen: Al-Qaeda in the Arabian Peninsula was formed by a merger of the Yemeni and Saudi branches of al-Qaeda in 2009. The group is believed to have orchestrated numerous high profile attacks outside Yemen, most notably the attack against Charlie Hebdo in Paris on 7 January 2015. The relationship between al-Qaeda in the Arabian Peninsula, Ansar al-Shari’a Yemen and al-Qaeda in the Arabian Peninsula is not known, with many considering that the former is a simply naming exercise in order to attract more local fighters. Stanford University, Mapping Militant Organisations: Al Qaeda in the Arabian Peninsula, 12 May 2015; S. Haddad, ‘Yemen’ L. Arimatsu and M. Choudhury (eds), The Legal Classification of the Armed Conflicts in Syria, Yemen and Libya, Chatham House, 2014, pp 26. Ansar al-Shari’a is listed as an alias for al-Qaeda in the Arabian Peninsula on the Security Council ISIL (Da'esh) & Al-Qaida sanctions list. See the permanent reference QDe.129 Al-Qaida in the Arabian Peninsula on the sanctions list.
- Southern Movement. The Southern Movement is a secessionist movement that emerged in 2007. Against the background of the conflict with the Houthis, the Southern Movement allied itself with President Hadi. In Spring 2017, the Southern Movement formed the Southern Transitional Council and turned against the governmental forces in 2018.