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International armed conflicts in Syria

Conflict type: International armed conflict

Syria is currently involved in multiple, parallel international armed conflicts (IACs) against the so-called ‘Global Coalition’ (led by the United States), Turkey, and Israel. It is worth recalling that Turkey is occupying parts of the northern territory of Syria, while Israel has been occupying the Golan Heights since 1967.

Several parallel international armed conflicts are occurring in Syria, notably against the US-led coalition, Turkey, and Israel:

According the view adopted by the RULAC project, an international armed conflict exists whenever states carry out military operations directed against non-state armed groups in the territory of another state without the latter’s consent, regardless of whether or not the territorial state responds with armed force or whether there are actual clashes between the armed forces of the states involved. This position does not exclude that there may be a parallel non-international armed conflict between the intervening state and the targeted non-state armed group, provided that the criteria for a non-international armed conflict are fulfilled.

As a final remark, it must be noted that the classification of the foreign intervention in Syria as an international armed conflict as per the lack of the latter’s consent does not change the classification of the conflict against the Islamic State, which remains a non-international one. Moreover, the operation against the Islamic State can be classified as a single non-international armed conflict that extends across Syria and Iraq.

Similarly, the non-international character of the confrontations between Turkey and the Islamic State and Kurdish groups, as well as for the armed clashes between Israel and Hezbollah, does not change due to foreign interventions.

Operations against the Islamic State, Al-Qaeda, and Kurdish armed groups in Syria

The US-led coalition

The US-led coalition was created in September 2014 and is currently formed by 85 members, in particular the US, Australia, Belgium, Canada, Denmark, France, Germany, Italy, Jordan, Morocco, the Netherlands, Saudi Arabia, Turkey, the UAE, and the UK. US Department of State, The Global Coalition to Defeat ISIS; The Global Coalition, 83 Partners United in Ensuring Daesh’s Enduring Defeat. Since the beginning of its mandate, it has carried out almost 20,000 strikes in Syria. US-led Coalition in Iraq and Syria, Airways, 2021. In December 2018 the US partially withdrew its troops from Syria. According to its official website, in 2020 the Global Coalition liberated Daesh’s last stronghold in Syria (the city of Baghouz). However, the coalition remains in the territory for prevention and stabilization and continues to carry out joint operations with the Syrian Democratic Forces against Daesh cells in northeast Syria. See the official website of the Global CoalitionJeff Seldin, ‘Islamic State operatives, US-backed forces clash in Syria’, VOA News, 21 January 2022; International Crisis Group, Crisis Watch, January 2022. For instance, heavy clashes took place in January 2022 following the largest-scale attack conducted by Islamic State since 2019. They launched an attack on the Kurdish-run Ghwayran/al-Sina’a prison in al-Hasakah in order to free Islamic State fighters.  In response, the Syrian Democratic Forces, supported by the US-led coalition, killing over 500 people, including 370 Islamic State fighters. Moreover, on 3 February 2022, a raid carried out by US special forces caused the death of ISIS leader Abu Ibrahim al-Hashimi al-Qurayshi and of several other ISIS fighters. ‘Kurdish-led forces in Syria recapture prison from ISIL’, Al Jazeera, 26 January 2022; ‘Islamic State leader Abu Ibrahim al-Qurayshi killed in Syria, US says’, BBC, 4 February 2022; International Crisis Group, Crisis Watch, January - February 2022.

Over the past years, official representatives of the Syrian Government have expressed their lack of consent over the attacks directed to ISIL and Al-Qaeda on their territory. Notably, the Permanent Representative of Syria to the United Nations has stated on multiple occasions that Syria has not consented to the intervention and that the operations are therefore carried out in violation of international law. Identical letters dated 17 September 2015 from the Permanent Representative of the Syrian Arab Republic to the United Nations addressed to the Secretary-General and the President of the Security Council, UN Doc. S/2015/719 (2015). It should be noted that at first Syria did not protested against the US-led intervention, thus raising the question as to whether it was tacitly consenting to the military operations on its territory. Nevertheless, since September 2015 the Syrian government has reiterated the absence of its consent to the intervention conducted by the US-led coalition. Accordingly, the intervening states have invoked self-defence to justify the use of force against ISIS in Syria.


After a gradual involvement in the Syrian civil war, Turkey started its direct military operations in 2016 against the Islamic State and the Kurds in Syria, without the consent of the Syrian Government. M. Coker, ‘Turkey Launches Fresh Incursion Into Syria’, The Wall Street Journal, 3 September 2016.

Turkey's air and ground operations in Syria target both the Islamic State group and the Kurdish People's Protection Units YPG, an offshoot of the PKK. Wary of an autonomous Kurdish region in Syria, Turkey seeks to prevent the establishment of a contiguous Kurdish region between Afrin and Kobane. In January 2018, Turkey and allied Syrian rebels, namely the Free Syrian Army (FSA), initiated a ground offensive against the Kurdish militia in Afrin. K. Shaheen, ‘Turkey Starts Ground Incursion into Kurdish-Controlled Afrin in Syria’, The Guardian, 21 January 2018; E. Cunningham and L. Loveluck, ‘Turkey says its troops have entered Syria in fight against Kurdish militias’, The Washington Post, 21 January 2018. Clashes and armed confrontations between Turkey and Turkish-backed groups against Kurdish militias continued up to 2021. K. Al-Khateb, ‘New Kurdish Group in Syria attacks Turkish-backed opposition in Afrin’, Al Monitor, 24 April 2021. Turkish operations against the YPG in Syria have been continuing in 2021 and 2022. A. M. Alhas, ‘Turkish army thwarts YPG/PKK attacks in northern Syria’, AA, 20 March 2021; Suzan Fraser, ‘Turkish jets target Kurdish positions in Iraq, Syria; 4 die’, ABC News, 2 February 2022; Jared Szuba, ‘Turkey steps up attacks on Syria’s Kurds amid Iraq operation’, AL-Monitor, 22 April 2022; International Crisis Group, Crisis Watch, April 2022.

Since August 2016, Turkey has occupied part of northern Syria. In October 2017, it deployed troops in the northern Syrian province of Idlib as part of the de-escalation zone agreed upon with Russia and Iran. J. Dettmer, 'Turkey Deploys More Forces in Northern Syria', VOA, 3 November 2017; W. Frangieh, 'Hostility Toward Militants Grows in Idlib as Turkey Deploys Troops', Syria Deeply, 23 October 2017; S. Al-Khalidi, 'Turkish Army Expands Deployment in Syria's Northwest: Rebels', Reuters, 15 October 2017. Furthermore, in January 2018 Turkey initiated a new air and ground campaign against the Kurdish militia in Afrin, backed by Syrian rebel groups, in particular the Free Syrian Army (FSA). K. Shaheen, 'Turkey Starts Ground Incursion into Kurdish-Controlled Afrin in Syria', The Guardian, 21 January 2018.

Operations against Iranian and Hezbollah targets in Syria

The lack of Syrian consent to the operations carried out by Israel and the US against Hezbollah and Iranian targets in Syria confirm the existence of two IACs between the countries involved.


Over the past years, Israel has conducted airstrikes against Iranian and Hezbollah objectives located in Syria. The Syrian Government denied its consent and accused Israel of committing acts of aggression against the Syrian territory. Letter dated 10 May 2018 from the Chargé d’affaires a.i. of the Permanent Mission of the Syrian Arab Republic to the United Nations addressed to the Secretary-General and the President of the Security Council, S/2018/447, 15 May 2018. On the other hand, Israeli military activities have intensified in 2021. Israel's military activities on Syrian territory have continued unabated since then. There have been monthly reports of air raids and missile attacks in 2022, causing serious material damage but also allegedly resulting in the death of Syrian soldiers. ‘Syria says Israel strikes southern Damascus; Iranian base hit’, Al Jazeera, 20 July 2020; S. Al-khalidi, ‘Israel intensifying air war in Syria against Iranian encroachment’, Reuters, 22 April 2021; ‘Israel fires missiles on border positions inside Syria – Syrian military’, Reuters, 23 February 2022; Emanuel Fabian and Toi Staff, ‘Syria says three soldiers killed in Israeli strikes near Damascus’, The Times of Israel, 24 February 2022; ‘Israeli air raids target positions in Syria’, Al Jazeera, 9 April 2022; ‘Syria: Israeli missile attack near Damascus’, Al Jazeera, 15 April 2022; Emanuel Fabian and Toi Staff, ‘Israel said to strike Syrian Golan in missile attack; damage reported’, The Times of Israel, 11 May 2022; International Crisis Group, Crisis Watch, May 2021 – April 2022.

In May 2018, the Quds Forces – a Special Forces unit of the Iranian Revolutionary Guards –allegedly fired 20 rockets on the Israeli-occupied Golan Heights from Syrian. In response, Israel launched a series of attacks against Iranian military targets in Syria, while Iran denied the its responsibility for the attacks. O. Alabaster, ‘Did Iran Attack Israel from Syria and why would they?’, The Independent, 10 May 2018; I. Kershner, ‘Iran Fires Rockets Into Golan Heights from Syria, Israelis Say’, The New York Times, 9 May 2018; ‘Israel responds after Iran ‘fires rockets’ at occupied Golan’, Al Jazeera, 10 May 2018. In January 2019 Israel Defence Forces (IDF) allegedly attacked Iranian targets in and around the capital Damascus, notably a training camp, munitions storage depots, and a site at Damascus International Airport. O. Liebermann, ‘Israel strikes Iranian targets in Damascus after missile fired at Golan Heights’, CNN, 22 January 2019; J. A. Gross, ‘Iran to respond to ‘Israeli Aggression’ in Syria official says’, The Times of Israel, 2 May 2018. The airstrikes in response to the Iranian attacks in the Golan Heights may be considered a distinct international armed conflict. Indeed, the use of force by the Israeli government against Iranian targets in Syria amounts to a parallel international armed conflict between Israel and Iran, on Syrian territory. Israel continued these attacks on Iranian targets. For instance, The Syrian Observatory for Human Rights reported that an Israeli air raid near Damascus on 27 April 2022 targeted munitions depots and military presence linked to Iran. ‘Israeli air raids in Syria kills nine: War monitor’, Al Jazeera, 27 April 2022; ‘Israel launches deadly air strikes on ammunition depot, target in Syria’, France 24, 27 April 2022.

The US

In February 2021 the US carried out an airstrike against armed groups supported by Iran, including members of Kata’ib Hezbollah, an Iraqi insurgent group founded in 2007. V. Romo, ‘US Launches Military Airstrikes Against Iranian-Backed Militants in Syria’, NPR, 25 February 2021; Stanford Center for International Security and Cooperation, Kata’ib Hezbollah. Representatives of the Syrian Government stated that the attack was an ‘act of aggression’, thus clarifying that they have not consented to such military operations on Syrian territory. Identical letters dated 26 February 2021 from the Permanent Representative of the Syrian Arab Republic to the United Nations addressed to the Secretary-General and the President of the Security Council, S/2021/197, 3 March 2021. The US launched rockets in April 2022, supported by their partners in the International Coalition, as a reaction on an attack on a US military base on 7 April 2022. With this rocket strike, the coalition targeted positions of Iranian-backed militias. ‘Four U.S. personnel injured in Syria attack – officials’, Reuters, 7 April 2022; International Crisis Group, Crisis Watch, April 2022; Tess Bridgeman and Brianna Rosen, ‘Still at War: The United States in Syria’, Just Security, 29 April 2022.

Operations against the Syrian government

For the official position adopted by RULAC it is not necessary that that the use of force is directed to the territorial State in order to apply the law of international armed conflict. Nevertheless, it this case all parties – i.e. the US-led coalition, Turkey, and Israel – have targeted Syrian military objectives and/or have occupied portions of its territory. This confirms the existence of parallel international armed conflicts.

US-led coalition

In response to the Syrian government's use of chemical weapons, the United States conducted missile strikes against a Syrian Air Force airfield on 7 April 2017. ‘Syria chemical ‘attack’: What we know’, BBC, 26 April 2017; A. Barnard and M. R. Gordon, ‘Worst Chemical Attack in Syria in Years; US Blames Assad’, The New York Times, 4 April 2017; US Department of Defense, Statement from Pentagon Spokesman Capt. Jeff Davis on US Strike in Syria, 6 April 2017; S. Almukhtar, K. K. R. Lai, S. Peçanha and K. Yourish, ‘Mapping the Targets of the American Military Attack on Syria’, The New York Times, 7 April 2017. In May and June 2017, the US also conducted strikes against Syrian government forces or pro-government militias to prevent them from advancing towards the area of operations of US special forces working with armed opposition groups and shot down a Syrian government fighter plane. M. Ryan, ‘US Launches Rare Intentional Strike on Pro-Government Forces in Syria’, The Washington Post, 19 May 2017; T. Gibbons-Neff, ‘US Conducts New Strikes on Pro-Syrian-Government Forces Threatening US Special Operations Base’, The Washington Post, 6 June 2017; T. Gibbons-Neff and K. Fahim, ‘US Aircraft Shoots Down a Syrian Government Jet Over Northern Syria, Pentagon Says’, The Washington Post, 18 June 2017.

In April 2018, a chemical attack took place on Douma, Eastern Ghouta. The Organisation for the Prohibition of Chemical Weapons (OPCW) specified that initials tests on samples from Douma confirmed ‘various chlorinated organic chemicals.’ Following the attack, the US, UK, and France responded with strikes against key government targets in Syria, notably a scientific research centre in Damascus, chemical weapons storage facilities and a command post. K. Calamur, ‘How will this attack on Syria be any different?’, The Atlantic, April 2018; H. Cooper, T. Gibbons-Neff and B. Hubbard, ‘US, Britain, and France Strike Syria Over Suspected Chemical Weapons Attack’, The New York Times, 13 April 2018. In 2020, another exchange of fire occurred between the US-led coalition forces and the Syrian ones. A. Aji, ‘Syria says US forces clash with Syrian troops, killing 1’, BBC, 17 August 2020; ‘US-led Coalition Clashes With Syria Regime Loyalists’, International Business Times, 02 December 2020.

After this last exchange of fire between the US-led coalition and the Syrian regime, no direct confrontations between both sides were reported. However, this does not change the classification of the conflict as an IAC. The situation remains very unstable and it would be premature to conclude that the chances of hostilities resuming between both parties are limited. Moreover, the Coalition remains present in Syria, carrying out attacks against non-state armed groups present on the ground, without the consent of the Syrian government. Accordingly, this therefore amounts to a classification of the situation as an IAC.


Turkish and Syrian forces exchanged fire in February 2020 in Idlib, Latakia, and in northern Aleppo. ‘The number of Turkish soldiers killed by regime fire on “Tarnabeh” military post rises to eight’, SOHR, 03 Feburary 2020; S. Fraser, ‘8 Turkish personnel, 13 Syrian troops killed in north Syria’, AP News, 03 February 2018. In the same month, at least 33 Turkish soldiers were killed by the Syrian governmental forces. G. Tuysuz and I. Sariyuce, ‘At least 33 Turkish soldiers killed in an air attack by Syrian regime, Turkish governor says’, CNN, 28 February 2020. As a consequence, the Turkish government initiated military operations against the Syrian army, which were supported by Russia, in Idlib. S. Demirtas, ‘Turkey launches Operation Spring Shield’, Hurriyet Daily News, 02 March 2020. Russia and Turkey agreed on a ceasefire in March 2020. ‘Syria war: Idlib ceasefire between Russia and Turkey begins’, BBC, 06 March 2020.

Despite this ceasefire agreement, indirect confrontations between the Syrian regime, supported by Russia, and Turkish-backed militias escalated from September 2021.  For instance, Russia launched an airstrike on 26 September 2021 killing over 11 Turkish-backed militants in Aleppo. This was countered by a guided missile attack by the Turkish-backed militias, which killed 2 Syrian soldiers. However, despite violations on both sides resulting in the death of Turkish and Syrian soldiers, the ceasefire of March 2020 remained in force. Mohammed Hardan, ‘Russia intensifies Idlib attacks ahead of summit with Turkey, Iran on Syria’, Al-Monitor, 23 September; Sara Firth, ‘Civilians bear the brunt of escalating violence in Syria’s Idlib’, Al Jazeera, 23 August 2021; International Crisis Group, Crisis Watch, Septmeber 2021 - April 2022.

It is worth recalling that Turkey still occupies part of the northern territory of Syria.


Technically, after the Yom Kippur war (1974) Syria and Israel have agreed on a ceasefire which is still lasting today. However, after the breakout of the hostilities in Syria, a number of confrontations between the two countries, especially in the Golan Heights, have occurred, more recently in 2020 and 2021. ‘Israel Carries Out Airstrike on Syrian Anti-Aircraft Battery’, The New York Times, 16 October 2017; Z. Tahhan, ‘Why does Israel keep attacking Syria?’, Al Jazeera, 23 October 2017; ‘Israel strikes Syrian army bases after Golan Heights attack’, BBC, 04 August 2020. Furthermore, Israel has captured the Syrian Golan Heights in 1967 and still occupies the territory.

Syria, Turkey, the United States and the other members of the coalition are party to the four 1949 Geneva Conventions. Syria, Australia, Belgium, France, Germany, Jordan, the Netherlands, Saudi Arabia, the United Arab Emirates and the United Kingdom are also a party to the 1977 Additional Protocol I applicable to international armed conflicts. In addition, they are bound by customary international humanitarian law applicable 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.

Last updated: Tuesday 24th May 2022