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International armed conflict in Ukraine

Conflict type: International armed conflict

Since July 2014 there has been an international armed conflict between Ukraine and Russia, in parallel to the ongoing non-international armed conflict in Ukraine. Furthermore, Russia is occupying Crimea.

There has been an international armed conflict between Ukraine and Russia since July 2014 in parallel to the ongoing non-international armed conflict in eastern Ukraine between Ukrainian pro-Russian rebels and Ukrainian government forces. In addition, Russia is also occupying Crimea.

For an international armed conflict (IAC) to exist, there must have been a resort to armed force involving at least two states. The threshold for an IAC is very low and does not require a certain intensity or duration. The existence of an international armed conflict is to be determined by the facts, not the subjective intent of the belligerents. For further information, see the Classification section.

Following the protests of Euromaidan and the consequent fall of the Ukrainian president Viktor Yanukovich in February 2014, Russian soldiers without distinctive insignias allegedly arrived in Crimea, took control of strategic positions, and captured the parliament in Crimea. ‘From 'Not Us' To 'Why Hide It?': How Russia Denied Its Crimea Invasion, Then Admitted It’, Radio Free Europe Radio Liberty, 26 February 2019. In April, concurrent Anti-Maidan demonstrations held by pro-Russian separatists in Donbass (east Ukraine) turned into armed confrontations with the Ukrainian armed forces. After capturing local government buildings, the separatists declared the creation of Donetsk and Luhansk People’s Republics. ‘Armed pro-Russian insurgents in Luhansk say they are ready for police raid’, Kyiv Post, 12 April 2014.

From the outset, Ukraine has consistently claimed that Russian soldiers were participating in the fighting in eastern Ukraine. However, Russia has denied these allegations, claiming that the Russians fighting in Ukraine are volunteers, including discharged members of the Russian army. ‘Ukraine Crisis: Thousands of Russian Fighting in East’, BBC, 28 August 2014, M. Urban, ‘How Many Russians Are Fighting in Ukraine?’, BBC, 10 March 2015. Ukraine has repeatedly captured Russian servicemen in eastern Ukraine. 'Captured Russian Troops "in Ukraine by Accident", BBC, 26 August 2014; A. Luhn, 'Russian Soldiers Captured in Ukraine to Face Trial on Terrorism', The Guardian, 18 May 2015. Locals have also repeatedly claimed that Russian soldiers were fighting alongside rebels. S. Walker, A. Luhn, 'Tension High in Ukrainian Border Towns Menaced by Russian Forces', The Guardian, 30 August 2014. In July 2014, Ukraine accused Russia of having shot down a Ukrainian military plane. 'Ukraine Conflict: Russia Accused of Shooting Down Jet, BBC, 17 July 2014. Both have accused each other of cross-border shelling. 'Ukraine and Russia Claim Cross Border Fire', Al-Jazeera, 25 July 2014. Based on the analysis of satellite images and social media, there is mounting evidence of crossborder artillery shelling since 14 July 2014. Bellingcat, Origin of Artillery Attacks on Ukrainian Military Positions in Eastern Ukraine between 14 July 2014 and 8 August 2014, 15 January 2015; S. Case, Putin's Undeclared War: Summer 2014 - Russian Artillery Strikes Against Ukraine, Bellingcat, 21 December 2016; S. Frizell, 'U.S: Satellite Imagery Shows Russian Shelling Easter Ukraine, Time, 27 July 2014. Finally, there are many reports of Russian soldiers having died in Ukraine. O. Boldyrev, 'Ukraine Conflict: Russian Families Look For Soldier Sons', BBC, 28 August 2014; A. Luhn, 'They were Never There: Russia's Defence for Families of Troops Killed in Ukraine', The Guardian, 19 January 2015.

While at the beginning of 2014 Russian President Putin claimed that the armed forces participating in the capture of the Verkhovna Rada of the Autonomous Republic of Crimea were local forces, in November 2014 he openly acknowledged that the Russian army participated in the annexation of Crimea. ‘Путин признал, что российская армия блокировала украинскую в Крыму’, Украинская правда, 17 November 2014. Furthermore, in December 2015, President Putin admitted the presence of Russian military specialists in Eastern Ukraine. During a press conference, after being asked about the capture of two Russian military intelligence officers in Ukraine, the Russian President conceded that there are Russian officers operating in the country: ‘[w]e never said there were not people there who carried out certain tasks including in the military sphere.’ Nevertheless, he stressed that this was ‘not the same as regular Russian troops.’ ‘Putin admits Russian military presence in Ukraine for first time’, The Guardian, 17 December 2015.

On 25 November 2018, three Ukrainian Navy vessels were fired upon and then captured by the Russian Federal Security Service (FSB) when they attempted to pass from the Black Sea into the Sea of Azov heading towards the port of Mariupol. 24 Ukrainians were captured and sent to prison to Moscow. According to the 2003 Treaty between the Russian Federation and Ukraine on Cooperation in the Use of the Sea of Azov and the Kerch Strait, the strait and the Azov sea are intended to be shared waters between the two states. Nevertheless, Russia claims that Ukraine should ask permission before entering the waters along the Crimean perimeter. Following the incident, the Ukrainian President Petro Poroshenko declared martial law along the Ukrainian border with Russia, which was approved by the Parliament and lasted until 26 December 2018. ‘The Kerch Strait incident’, International Institute for Strategic Studies (IISS).

The United Nations General Assembly (UNGA) adopted a resolution on the matter, titled ‘The problem of militarization of the Autonomous Republic of Crimea and the city of Sevastopol (Ukraine), as well as parts of the Black Sea and the Sea of Azov’, where it called for the release of Ukraine’s vessels and crew members Russia captured. Furthermore, it condemned ‘the construction and opening of the Kerch Strait bridge between the Russian Federation and temporarily occupied Crimea, which facilitates the further militarization of Crimea’ and ‘the increasing military presence of the Russian Federation in parts of the Black Sea and the Sea of Azov, including the Kerch Strait, and the Russian Federation’s harassment of commercial vessels and restriction of international shipping there.’ UNGA, Problem of the militarization of the Autonomous Republic of Crimea and the city of Sevastopol, Ukraine, as well as parts of the Black Sea and the Sea of Azov, UN Doc. A/73/L.47, 5 December 2018.

On 16 September 2016, Ukraine instituted arbitral proceedings against Russia under Part XV and Annex VII of the 1982 United Nations Convention on the Law of the Sea (UNCLOS). On 25 May 2019, the International Tribunal for the Law of the Sea (ITLOS) adopted provisional measures. Specifically, it required ‘the Russian Federation to release the three Ukrainian naval vessels and the 24 detained Ukrainian servicemen and to allow them to return to Ukraine in order to preserve the rights claimed by Ukraine.’ However, it did not consider it necessary to require the Russian Federation to suspend criminal proceedings against the 24 detained Ukrainian servicemen and refrain from initiating new proceedings.’ On the other hand, it ordered ‘both Parties to refrain from taking any action which might aggravate or extend the dispute submitted to the Annex VII arbitral tribunal.’ ITLOS, Case Concerning the Detention of Three Ukrainian Naval Vessels (Ukraine v Russian Federation), Request for the prescription of provisional measures, Order, No. 26, 25 May 2019, §§118-119.

All these factors combined point towards direct Russian involvement in eastern Ukraine, directly in hostile encounters with Ukrainian forces and in support of the rebels since July 2014. Hence, in addition to the non-international armed conflicts between the rebels and the government, there appears to be a parallel international armed conflict between Ukraine and Russia.

Nevertheless, it is worth noting that the Russian involvement does not turn the NIAC between Ukraine and the self-proclaimed ‘People’s Republics’ of Donetsk and Lubansk into an IAC. As clarified by the International Criminal Tribunal for the Former Yugoslavia (ICTY) in its seminal Tadic decision, ‘in order to attribute the acts of a military or paramilitary group to a State, it must be proved that the State wields overall control over the group, not only by equipping and financing the group, but also by coordinating or helping in the general planning of its military activity.’ ICTY, The Prosecutor v Duško Tadic, Appeals Chamber, Judgment, IT-94-1-A, 25 July 1999, §131. For further information on the question of control, see the Classification section. While evidence suggests that Russia is training and equipping the armed groups and providing them with weapons, M.R. Gordon, ‘Russia Continues to Train and Equip Ukraine Rebels, NATO Official Says’, The New York Times, 4 November 2014. This does not amount to overall control per se: as aforementioned, ‘coordinating or helping in the general planning of its military activity’ are also required to make IHL of international armed conflicts exclusively applicable. ICTY, The Prosecutor v Duško Tadic, Appeals Chamber, Judgment, IT-94-1-A, 25 July 1999, §131. Based on the information at our disposal, it is not possible to conclude with a degree of certainty that Russia is exercising overall control over the opposition groups operating in Ukraine.

It must however be mentioned that in November 2019 the International Court of Justice (ICJ) affirmed that it has jurisdiction on the case Application of the International Convention for the Suppression of the Financing of Terrorism and of the International Convention on the Elimination of All Forms of Racial Discrimination, filed by Ukraine against Russia over Moscow's alleged support of pro-Russian separatists and discrimination in annexed Crimea. ICJ, Application of the International Convention for the Suppression of the Financing of Terrorism and of the International Convention on the Elimination of All Forms of Racial Discrimination (Ukraine v. Russian Federation), 2019. Information appearing in the merits phase and the judgment of the ICJ could lead to the conclusion that Russia had the requisite overall control over the opposition groups operating in Ukraine.

In 2021, tensions between Russia on the one hand and Ukraine and a number of western countries on the other have escalated. Since US President Biden took office in January 2021, Ukrainian President Volodymyr Zelensky adopted a more assertive strategy vis-à-vis Russia, while starting a discussion regarding the possibility to join NATO. As a reaction, Putin started deploying Russian troops at the Ukrainian border. On the other hand, on 26 October 2021, Ukraine ‘destroyed a D-30 howitzer used by Russian-backed separatists in the eastern Donbas region’ using a Turkish drone. Furthermore, in November US warships were found sailing in the Black Sea, while satellite imagery showed an increased number of Russian troops close to the border with Ukraine. In December, Biden announced that Western countries would adopt sanctions against Russia, should it invade Ukraine, while Putin demanded that Western countries and NATO cease all military activities close to Ukraine and that the latter will not be accepted as member of NATO. In January and February 2022, diplomatic attempts to de-escalate proved unsuccessful. L. Ragozin, ‘Russia-US escalation: How did we get here?’, Al Jazeera, 21 December 2021; ‘Timeline: How did the recent Ukraine-Russia crisis start?’, Al Jazeera, 13 February 2022; I. Khurshudyan and D. L. Stern, ‘Why Ukraine’s Turkish-made drone became a flash point in tensions with Russia’, The Washington Post, 15 January 2022;  ‘U.S. navy ship tracked by Russia on entry to Black Sea’, Reuters, 4 November 2021.

On 21 February, Putin formally recognized independence of separatist regions in eastern Ukraine. In a televised announcement, he affirmed that ‘I deem it necessary to make a decision that should have been made a long time ago – to immediately recognize the independence and sovereignty of the Donetsk People’s Republic and the Luhansk People’s Republic.’ In the meantime, Putin deployed more troops to the border with Ukraine. The day after, Russian President ordered troops to enter easter Ukraine and claimed that they have a peacekeeping function. ‘Ukraine crisis: Russia orders troops into eastern Ukraine’, BBC, 22 February 2022; ‘Putin recognises independence of Ukraine breakaway regions’, Al Jazeera, 22 February 2022.

On 24 February 2022, Russian forces entered Ukraine and began targeting military objectives close to the major Ukrainian cities. During the following hours, airstrikes continued and extended to other areas of Ukraine, including the capital Kyiv. Attacks started being conducted against civilians too. For instance, it has been reported that an apartment complex outside of Kharkiv – one of the main cities of Ukraine – was directly targeted. On 25 February, rocket strikes have hit Kyiv, while Russian tanks have been seen approaching the capital. At least at least 100,000 people have been displaced, while neighboring countries prepare to receive refugees. ‘Ukraine conflict: Simple visual guide to the Russian invasion’, BBC, 25 February 2022; ‘Ukraine slams ‘horrific’ strikes on Kyiv amid Russian advance’, Al Jazeera, 25 February 2022.

Involvement of Belarus

Since February 2022, Belarus has allowed Russia to use its territory to conduct the aggression against Ukraine. ‘Ukraine conflict: UK sanctions Belarus for role in Russian invasion Russia-Ukraine war’, BBC, 1 March 2022. According to the UNGA Definition of aggression, Resolution 3314 (1974), Article 3(f): ‘The action of a State in allowing its territory, which it has placed at the disposal of another State, to be used by that other State for perpetrating an act of aggression against a third State.’ Accordingly, Belarus is committing an act of aggression against Ukraine. However, whether this means that Belarus is party to an IAC against Russia is controversial. On the one hand, the ICRC Commentary to Article 2 common to the Geneva Conventions says that ‘the notion of armed conflict under Article 2(1) requires the hostile resort to armed force involving two or more States.’ ICRC Commentary to Article 2 common to the Geneva Conventions, §218. On the other hand, some authors posit that an act of aggression, even without resort to force, would be sufficient to trigger a NIAC. See e.g. A. Wentker, ‘At War: When Do States Supporting Ukraine or Russia become Parties to the Conflict and What Would that Mean?’, EJIL:Talk!, 14 March 2022.

Views of parties to the conflict and other actors

Since 2014, the UN Security Council has conducted over 40 meetings discussing the issue of Russian aggression against Ukraine. ‘Russian Aggression’, Permament Mission of Ukraine to the United Nations in New York.

In November 2016, the Office of the Prosecutor of the International Criminal Court concluded in its Report on Preliminary Examination Activities that the available information 'would suggest the existence of an international armed conflict in the context of armed hostilities in eastern Ukraine from 14 July 2014 at the latest, in parallel to the non-international armed conflict.' Office of the Prosecutor, Report on Preliminary Examination Activities, November 2016, §169. For a contrary view, albeit reached at an earlier point in time, see R. Heinsch, ‘Conflict Classification in Ukraine’, International Law Studies 91 (2015), U.S. Naval College of War, p 354.

Following Russian invasion of Ukraine started on 24 February 2022, a number of countries and organizations have condemned the military intervention. The UN Secretary General asked Putin to deescalate: ‘In the name of humanity, do not allow a war to start in Europe which could be worst war since the beginning of the century with consequences not only devastating for Ukraine, not only tragic for the Russian Federation but with an impact cannot even foresee.’ US President Biden defined Russian military action and ‘unprovoked and unjustified attack.’ UK Prime Minister Boris Jonson affirmed that: ‘Today, in concert with our allies, we will agree a massive package of economic sanctions designed in time to hobble the Russian economy.’ Furthermore, G7 leaders affirmed that: ‘this crisis is a serious threat to the rules-based international order, with ramifications well beyond Europe.’ On the other hand, China rejected the qualification of Russian actions as an invasion and called ‘ on all sides to exercise restraint to prevent the situation from getting out of control.’ ‘World reacts to Russia’s attack on Ukraine’, Al Jazeera, 24 February 2022.

Both Russia and Ukraine are parties to the four 1949 Geneva Conventions and the 1977 Additional Protocol I. In addition, they are bound by customary international humanitarian law applicable to 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 5th April 2022