The Kerch Strait Incident: Law of the Sea or Law of Naval Warfare?

On Sunday 25 November 2018 Russian coast guard patrol boats, including the Don and the 630-ton Izumrud, first intercepted and later fired on three Ukrainian naval ships near the entrance to the Kerch Strait. Two Ukrainian sailors were injured, the Ukrainian ships seized and the crews arrested. The attack has been roundly condemned in the United States and around the world.

The Russian ships intercepted two Ukrainian Gyurza-M-class artillery boats, Berdyansk and Nikopol and a tugboat, Yany Kapu, as they sailed toward the Ukrainian port of Mariupol. Russian forces seized the vessels and arrested 24 crew members. The Don twice rammed the tugboat and the Russian vessels opened fire on the two smaller Ukrainian warships. The incident occurred in the territorial sea along the approaches to the Kerch Strait, which is bordered in the east by Russia and in the west by Russian-occupied Ukrainian Crimea. The Russian government stated that its forces fired only after the Ukrainian ships violated articles 19 and 21 of the United Nations Convention on the Law of the Sea (UNCLOS) concerning innocent passage in the territorial sea.

Exploring the legal circumstances of the incident requires selection between peacetime rules of the law of the sea and the law of naval warfare, which applies to international armed conflicts. This post concludes that the actual incident on the water is part of a continuing aggression by Russia against Ukraine, in violation of the UN Charter. While unlawful as a matter of the jus ad bellum, the incident would be a lawful in bello use of force by Russia in accordance with the law of naval warfare, notwithstanding Russia’s unlawful invasion of Crimea in 2014 or subsequent unlawful treatment of the Ukrainian sailors as common criminals rather than prisoners of war. In this case the law of naval warfare is lex specialis and supplants mutatis mutandis the peacetime rules of the international law of the sea for Russia and the Ukraine.

Ukraine-Russia 2003 Bilateral Agreement

In 2003, Russia and the Ukraine signed the Agreement between the Russian Federation and the Ukraine on cooperation in the use of the sea of Azov and the strait of Kerch. The treaty recognizes free navigation of merchant ships and warships by both states through the strait. The agreement was accompanied by a Joint Statement that the Kerch Strait and Sea of Azov are constitute historic internal waters. Under the agreement, foreign warships may enter into the Sea of Azov only upon mutual consent of Ukraine and Russia. While the two states claimed the area as historic internal waters, their assertion of sovereignty over the strait has not been accepted by other states.

After Russia invaded Crimea in 2014 it occupied the western side of the strait, and in May 2018 opened a bridge across the Kerch Strait, which the Russians named the “Crimean Bridge.” The main span of the structure is just 33 to 35 m (108-115 ft) in height, limiting the type and size of ships that now may enter the Sea of Azov – a systemic impediment to the right of tall ships to conduct transit passage. The agreement also stipulates that Russian-Ukrainian maritime cooperation in the strait must be managed “by implementation of existing agreements” and in accordance with international law, such as UNCLOS. In this regard, Russia appears to have violated the 2003 agreement through its noncompliance with obligations under UNCLOS. Setting aside the historic internal waters assertion of 2003, the Ukraine now claims that the incident occurred in the territorial sea, rights and duties of which are set forth in UNCLOS.

Russian Violations of the Law of the Sea

Automatic identification transmissions from the Aviona, a Liberian-flagged ship at the scene, suggest the incident occurred at the center of the south side channel entering the Kerch Strait. The approaches to the Kerch Strait and the waters that run through it are part of the territorial sea of Russia on the eastern side of the strait and Russian-occupied Ukraine on the western side of the strait. Generally, the regime of innocent passage applies in the territorial sea in accordance with article 19 of UNCLOS. Russia has imposed pilotage requirements in the strait, apparently under article 21 of UNCLOS, which permits coastal states to adopt regulations for the safety of maritime traffic in the territorial sea. Russia states that the Ukrainian naval ships failed to heed orders to stop, as they were not allowed to transit the strait without a Russian pilot – a mandatory requirement for foreign-flagged ships. Pilotage is helpful to navigate particularly narrow passages and protect especially sensitive marine environments from challenging routes that may be at heightened risk of vessel source pollution caused by ship collision. The Kerch Strait, for example, has four bends and is 18.9 miles in length.

While the waters of the Kerch Strait are within the territorial sea of Russia and the Ukraine, it has an additional legal status under article 37 of UNCLOS as a strait used for international navigation, as it connects the Black Sea to the Sea of Azov. The Sea of Azov has an area of 39,000 km² (15,000 m²). If it were a lake it would rank 6th in the world—between Lake Michigan at 58,000 km² (22,000 m²) and Lake Tanganyika at 32,600 km² (12,600 m²). At its narrowest point, the Kerch Strait is just 3.1 km (1.9 m) wide. Article 38 of UNCLOS provides that all states enjoy the right of transit passage through such international straits. This right is customarily extended to the approaches to the strait. Transit passage is more permissive than innocent passage in that it permits overflight of the strait by aircraft and submerged transit by submarines, although states enjoying transit passage still must conduct transits continuously and expeditiously and refrain from threatening the coastal states or conducting military exercises in the strait, in accordance with article 39 of UNCLOS.

Assuming arugendo that UNCLOS would apply in this case, the Russian interception would be unlawful in a multitude of ways. If the incident reportedly occurred in Ukraine’s own territorial sea, then Russian warships conducted security patrols there in violation of innocent passage in an area under Ukrainian sovereignty. Supposing the attack occurred in the Russian territorial sea, Russian action was a violation of the right of innocent passage of the Ukrainian ships, which appear not to have acted inconsistent with article 19. Because the overlapping seas also form the center channel of the Kerch Strait, Russia’s requirement for compulsory pilotage is not authorized by article 21 UNCLOS. Russia appears to have adopted compulsory pilotage through Kerch Strait, which may not apply to foreign-flagged ships without adoption of such a requirement by the Member States of the International Maritime Organization (IMO). Since the IMO has not adopted any pilotage requirement, Ukraine’s ships enjoy the right to freedom of navigation through the strait. Russia’s compulsory pilotage in Kerch Strait violates article 42 of UNCLOS, which prohibits any regulation by coastal states bordering straits that “have the practical effect of denying, hampering or impairing the right of transit passage” through an international strait.

The attack on the Ukrainian ships was not an isolated event. Russia has been quietly choking Ukrainian maritime commerce that transits Kerch Strait, delaying and harassing ships bound to or from Ukrainian ports of Berdyansk and Mariupol on the Sea of Azov. This year maritime cargo turnover at the ports has declined 21 percent and 7 percent, respectively, due to Russian interference. Volodymyr Yelchenko, Ukraine’s Permanent Representative to the United Nations, fears Russia will seize the two ports, which are a conduit for agricultural and industrial trade between eastern Ukraine and the rest of Europe. Subsequent to the incident, Russia has anchored a large cargo vessel under the Kerch Strait bridge to block access through the strait – a continuing violation of article 39 and 42 of UNCLOS.

Russian Violation of Ukrainian Sovereign Immunity

Russia has been roundly criticized for violating Ukrainian rights to freedom of navigation through Kerch Strait and in this incident, the sovereign immunity of the Ukrainian warships. For example, professor Julian Ku at Hofstra Law School  and Alex Oude Elferink, director of the Netherlands Institute for the Law of the Sea, have stated that Russia clearly acted in violation of international law. The Ukrainian vessels are warships, which are defined in article 29 of UNCLOS as ships belonging to the armed forces; bearing the external marks distinguishing such ships of its nationality; under the command of an officer duly commissioned by the government of the state and whose name appears in the appropriate service list or its equivalent; and manned by a crew which is under regular armed forces discipline. Warships are protected by sovereign immunity as reflected in article 32 of UNCLOS and therefore are inviolable; no nation may exercise legal competence over them and their capture or arrest is unlawful. Furthermore, the attack on the Ukrainian ships appears to have occurred in the Ukrainian territorial sea, albeit under Russian occupation.

Even if a sovereign immune ship violates the regime of innocent passage in the territorial sea the only recourse for the coastal state is to “require it to leave the territorial sea immediately,” in accordance with article 32 of UNCLOS. Most scholars suggest that the lawful steps coastal states may take to require a foreign warship to leave the territorial sea do not include the use of force, although this view is not universal. Churchill and Lowe, for example, suggest that the coastal state may use force to compel warships not in innocent passage to leave the territorial sea. States have been rather reticent to use force against foreign warships in the territorial sea that are not in innocent passage, however, as illustrated by decades of state practice to warn but avoid attacking submarines intruding in the territorial sea. Taking at face value the Russian claim that the Ukrainian ships were not in innocent passage, Russia had no legal basis to assert jurisdiction over foreign sovereign immune naval ships, let alone shoot at them. In any event, Russia’s insistence that it took lawful measures against ships that were not in innocent passage ignores the more compelling legal regime – the law of naval warfare.

The Law of Naval Warfare

The law of naval warfare largely displaces UNCLOS in this case since the law of the sea is a peacetime regime and Ukraine and Russia are engaged in an international armed conflict (IAC). Yet Russia disputes that an IAC exists between it and Ukraine because it does not accept that there is an ongoing occupation of Crimea. In accordance para. 70 of the Tadić decision, however, an IAC exists whenever there is a resort to armed force between States and it is not dependent on its recognition by either party. Indeed, the conflict began in the early morning of Friday, February 28, 2014, when Russian armed forces left the Black Sea naval base near Sevastopol, Crimea and headed toward the Crimean regional capital of Simferopol.

During international armed conflict, international humanitarian law applies, and at sea, the associated rules of the law of naval warfare. Thus, the rules governing the naval incident near the Kerch Strait derive from customary humanitarian law and the Hague Conventions and Geneva Conventions rather than UNCLOS. These rules have are for the most part restated in the San Remo Manual on International Law Applicable to Armed Conflicts at Sea and permit targeting military objectives, such as enemy warships. See Rule 41 of the San Remo Manual. Rule 47 sets forth a list of non-military vessels not subject to attack, but these include hospital ships and small craft used in coastal rescue and are not implicated here.

As part of the Ukrainian Navy, the artillery patrol boats are part of a belligerent force and may be targeted for capture, or attacked and destroyed without warning by Russian armed forces at any time during hostilities, unless they are hors de combat. The warships contribute to Ukraine’s military action by their very nature, and their capture or destruction constitutes a military advantage for Russia.  These rules also apply to auxiliary vessels, such as the Ukrainian tugboat, which is reportedly a Ukrainian Navy craft. During peacetime, Rules 6, 7 and 8 of the Convention on the International Regulations for Preventing Collisions at Sea (COLREG) applies to the interception and collision of a tugboat by the Russian Coast Guard. During armed conflict, however, Russia’s action to collide with the tugboat appears to be a proportionate use of force against either a Ukrainian military asset, or a civilian craft that was integrated into the Ukrainian order of battle and therefore without noncombatant immunity.

While the Russian invasion of the Ukraine is an unlawful war of aggression in violation of article 2(4) of the Charter of the United Nations, now that the two nations are engaged in an IAC, Russian armed forces are entitled to target and destroy Ukrainian warships. During such engagements, Russian forces still must comply with principles of the law of war, such the principle of distinction, the principle of humanity, and the prohibition against unnecessary suffering and superfluous injury.

At the same time, the Ukrainian crew members are entitled upon capture to be treated humanely as lawful combatants. These service members must be accorded status as prisoner of wars under article 4 of the Geneva Convention Relative to the Treatment of Prisoners of War (GC III). Yet the Ukrainians have been charged with entering Russia with unauthorized weapons – a crime with a maximum sentence of six years.

The naval engagement raises larger issues of Russian treatment of Ukrainian civil and merchant ships in the region, especially coastal fishing vessels. Crimea was annexed to Russia on March 16, 2014. Under the authority of the Russian armed forces, the occupation extends throughout the land territory as well as the territorial sea. As an occupying power, Russia must respect merchant mariners as protected persons under article 27 of Convention relative to the Protection of Civilian Persons in Time of War (GC IV). Coastal fishing vessels are specifically protected from attack, as reflected in the Paquete Habana Case and article 47(g) of the San Remo Manual. As an occupying power, Russia has the right (and indeed the obligation) to assure public safety and order in the occupied territory in accordance with articles 27 and 64 of GC IV. For Ukrainian flagged vessels, adoption by Russia of mandatory pilotage through the Kerch Strait may be an expression of this right, but such measures may not be imposed on other foreign-flagged ships unless a compulsory pilotage scheme is adopted by the member states of the IMO.

Conclusion

Russia’s conduct is part of ongoing aggression since 2014 in violation of the Charter of the United Nations. Because of the existence of an IAC, however, Russia’s conduct is not a violation of UNCLOS, as the law of the sea is displaced by the law of naval warfare. If UNCLOS were to apply, Russia would be in violation of either its own obligations to operate in innocent passage in the Ukrainian territorial sea, or a violation of the right of innocent passage enjoyed by Ukrainian naval ships. Furthermore, Russia’s (and Ukraine’s) claim of internal historic waters in the Kerch Strait and Sea of Azov may be excessive, and the legality of Moscow’s adoption of compulsory pilotage is questionable. In either event, Russia’s interference with Ukrainian warships violates freedom of navigation under the peacetime regime of UNCLOS as well as the 2003 bilateral agreement on the Kerch Strait. While Russia’s attack on the Ukrainian warships and tug boat appear to be lawful uses of force within jus in bello associated with the invasion and occupation of Crimea, Russia’s treatment of the captured Ukrainian sailors as common criminals rather than prisoners of war violates international humanitarian law.

The incident demonstrates how adept Russia is at exploiting the seam between the contending peacetime and wartime legal dimensions of the Crimea conflict to create perceptions of a “gray zone” that effectively advance its geopolitical agenda while confusing and demoralizing its critics.