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

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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.


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.

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Himanil Raina says

December 3, 2018

You have stated that the Kerch Strait has an additional legal status under article 37 of the UNCLOS as a strait used for international navigation. However, Article 37 of the Law of the Seas Convention (LOSC) only applies to a strait used for international navigation between one part of the high seas or an exclusive economic zone and another part of the high seas or an exclusive economic zone.

The Sea of Azov however, contains no high seas nor any exclusive economic zones. It is an enclosed or semi enclosed sea as defined in in Part IX of the Law of the Sea Convention (LOSC). As per Article 123 of the LOSC, states bordering enclosed or semi enclosed seas are to cooperate in the exercise of their rights and the performance of their duties. Prior to the USSR’s dissolution in 1991, the Sea of Azov & the Kerch Strait were the USSR’s internal waters. While, Ukraine and Russia have not finished delimiting the area, they have recognized the Sea of Azov and the Strait of Kerch as the inland waters of Russia & Ukraine through two 2 bilateral treaties in 2003 (January & December). Hence, no question arises of there existing any high seas or an EEZ within the Sea of Azov, which is why the Strait of Kerch cannot constitute a strait used for international navigation as envisaged by Article 37. I would be very interested to hear about why this would not be the case. Regardless, it would be very beneficial to be directed to further literature detailing how Ukraine and Russia's assertion of sovereignty over the strait has not been accepted by other states.

G. Matteo Vaccaro-Incisa says

December 3, 2018

Thank you Professor Kraska for this excellent overview of the intertwine between peace and war time law in relation to the recent maritime incident around the Kerch strait.

In the context of the war/peace time 'gray zone' that you very clearly illustrated (yet, I'd dare say it's hardly only Russia that exploits it), I am perhaps not entirely convinced about the confirmation that an international armed conflict is in place because of the adoption of a HR committee report that: i) has another subject-matter and does not mention the concept of war, ii) passed only with a relative majority, the slimmest out of the 4 HR reports approved that day (the others were on North Korea, Syria, and Iran), and iii) some of the States that voted against are very significant in geopolitical terms (hence, in shaping the mentioned 'gray zone'; e.g., China and India) or are democracies (yet expressing views much different than the 'West' on the situation as a whole; e.g., India, Philippines, South Africa).

As it seems that both sides, even if for different reasons, agree in refusing to consider themselves at war with each other, nor they acknowledge their engagement in any sort of military operation, and that the concept of 'occupation' seems nowadays disengaged from that of war, perhaps it could be easier to conclude for the application of peace time law.

In this perspective, as you illustrated, the violation of UNCLOS becomes apparent, independently from the legality of the control over Crimea.

As a more 'political' side note, one may also consider that the 'incident' takes place in the context of upcoming elections in Ukraine, and shortly after an unpopular pension reform in Russia. Both Presidents need to regain popularity, and what's best than revamping nationalistic sentiments with an after all minor maritime 'incident'?

Vladislav says

December 3, 2018

Do you know that UA have adopted compulsory pilotage through Kerch Strait before 2014? Nowadays regulation change a little - bridge have in 35 meter in height, but those ships cannot go through because Azov is to shallow for them - only river type vessels can go throught Azov sea.
Here is the link to UA regulation -

Here a link which describes situation till 2014 -

Minh Tran says

December 4, 2018

Thank you for your post Professor Kraska!

After reading through your post, I must be in absolute agreement with your conclusion that “The incident demonstrates how adept Russia is at exploiting the seam between the contending peacetime and wartime dimensions of the Crimea conflict…”

If it is true that there is an IAC between Russia and Ukraine, and if it true that the law of war prevails over the peacetime law, the 2003 Agreement and the UNCLOS would not be applicable. Thus, one may well argue that there would be possible no violation of the 2003 Agreement, and no violation concerning immunities of warships, innocent passage, passage through straights used for international navigation, and compulsory pilotage under the UNCLOS. And, therefore, it appears to me that the only violation that Ukraine may invoke against Russia concerning the incident is the failure to grant the status of Prisoners of War to Ukrainian screw members by prosecuting them under ‘normal’ criminal law.

Lawyers of the Ukrainian Government may have a headache to choose which line of arguments to be advanced.

By the way, it is interesting to know the argument of Himanil Raina on the status of the Kerch Strait as a strait used for international navigation, and, especially, the information provided by Vladislav on how shallow the Sea of Azov is which may be an essential factor to judge whether the height of the Crimean Bridge breached of the rights to navigation.


Alexander Proelss says

December 4, 2018

Thank you, James, for this most interesting blogpost. Reading your text, I realized how much we often seem to tend to look at incidents such as the one in the Strait of Kerch through the lense of the sub-system of international law that we are the most familiar with. This is certainly true with regard to my initial assessment of the incident. Thus, it is particularly important that you addressed the relationship between the law of the sea on the one hand and international humanitarian law on the other in your post. That said, I do share some of the concerns expressed by Matteo Vaccaro-Incisa in his comment.

Notwithstanding some doubts that have been expressed in legal literature, there seems to be a good case to argue that an international armed conflict exists between Russia and Ukraine since July 2014 in parallel to the ongoing non-international armed conflict in eastern Ukraine between Ukrainian pro-Russian rebels and Ukrainian government forces. It has been stated that this extends to both Crimea (which ought to be regarded as occupied territory) and the situation in Eastern Ukraine (see, paras. 158 and 169). As you note, if an international armed conflict exists, the rules of naval warfare apply. Under these rules, no doubt exists that the parties to an international armed conflict are entitled to attack and capture ships flying the flag of a belligerent State.

As pointed out by Matteo, however, prior to the incident both States seem to have acted on the assumption that no international armed conflict exists between them. Russia does not seem to have officially declared blockade of the Strait of Kerch, nor has it taken any other measure of naval warfare until the incident relevant here. As far as can be seen, Russia has also not based its jurisdictional objections in the ongoing arbitration concerning Coastal State Rights in the Black Sea, Sea of Azov, and Kerch Strait on the inapplicability of the 1982 LOSC due to the existence of an armed conflict (admittedly, though, the Tribunal will have to assess ex officio whether it has jurisdiction to decide the case). You counter this argument by referring to the fact that under the law as it stands today, the existence of an armed conflict does not depend on its recognition by either party. Furthermore, under the Tadić decision, ʻinternational humanitarian law continues to apply in the whole territory of the warring States or, in the case of internal conflicts, the whole territory under the control of a party, whether or not actual combat takes place thereʼ (para. 70).

However, I find it difficult to accept in a situation such as the present one to argue, based on the rather formalistic approach taken by the ICTY, that the practice and viewpoint of the belligerent States as well as other international actors (note: in specific relation to the Sea of Azov) is irrelevant. The incident on 25 November 2018 seems to be the first case of open armed violence for which Russia has openly claimed responsibility since the unlawful annexation of Crimea (see In particular, if the available information is correct, no act of armed violence has so far been conducted in the Strait of Kerch and the surrounding waters, including the Sea of Azov, by one of the two States. Prior to the stopping and investigating of foreign ships by Russian authorities that commenced following the opening of the bridge over the Strait of Kerch, ships flying the flag of the two States had both used the strait as well as the Sea of Azov. Is it then really possible to argue four years after the beginning of an international armed conflict that Russia is entitled to attack and capture Ukrainian warships on the basis of the rules and principles of naval warfare? Would it not rather be more plausible to hold that Russia was legally prevented, in relation to navigation in the Strait of Kerch and the Sea of Azov, from suddenly making use of the methods of naval warfare? Arguably, the concept of estoppel could be referred to in order to provide a legal basis for this submission. In the alternative, in light of the practice of the relevant actors with specific regard to the Strait of Kerch and the Sea of Azov, perhaps the argument could be made that the existing armed conflict has so far not extended over the situation at sea where the two States have acted as if no armed conflict would exist between them.

Following this line of argument, Russia would then be under a duty to accept that the lawfulness of the specific operation against the Ukrainian ships ought to be assessed on the basis of the international law of the sea. If not justified by the right of self-defence, the Russian attack would constitute a breach of the prohibition of the use of force, which would then result in the application of international humanitarian law following the incident concerned. This seems to correspond with the position of Ukraine stating that ʻRussia has de facto expanded its military aggression against Ukraine to the seaʼ ( On 28 November 2018, Ukraine furthermore argued that its rights under the LOSC had been violated and that ʻall detained Ukrainian servicemen are protected by the norms of international humanitarian law, in particular the Geneva Convention Relative to the Treatment of Prisoners of War, 1949ʼ ( Notwithstanding the existence of an international armed conflict in Eastern Ukraine, the European Parliament adopted a resolution on the situation in the Sea of Azov prior to the specific incident (, by which it deplored ʻthe excessive actions of the Russian Federation in the Sea of Azov insofar as they breach international maritime law and Russia’s own international commitmentsʼ, and it condemned ʻthe excessive stopping and inspection of commercial vessels, including both Ukrainian ships and those with flags of third-party states, including ships under flags of various EU Member Statesʼ (para. 1). Furthermore, while expressing ʻits very serious concern about the very volatile security situation in the Sea of Azov, which could easily escalate to an open conflictʼ (para. 2), it expressly condemned ʻthe infringement of navigational rights in Ukraine’s territorial watersʼ. It also argued that ʻRussia is bound by international maritime law and the bilateral cooperation agreement with Ukraine not to hamper or impede transit passage through the Kerch Strait and the Sea of Azovʼ (para. 3). All this seems to militate in favour of accepting that the law of naval warfare has only become applicable following the incident of 25 November. In this respect, it is perhaps also not without relevance that the law of naval warfare does not completely displace the rules and principles of the international law of the sea. For example, it seems to be generally recognized that if a right of transit passage exists (which I think is subject to doubts, however, taking into account that the Strait of Kerch leads into the Sea of Azov, i.e., an area which prior to the dissolution of the Soviet Union used to be accepted as a single-State bay, and which, on the basis of the Cooperation Agreement of 2003 and customary international law, likely consists of joint internal waters of Russia and Ukraine still today (, this right may, at least as far as ships flying the flag of third States are concerned, not be hampered, notwithstanding the existence of an international armed conflict.

I would be very interested in your thoughts on this.

James Kraska says

December 4, 2018

Thank you all for the fantastic comments. Alexander, I especially appreciate your thoughts along with Matteo's comments concerning rule selection (law of naval warfare and law of the sea). I also see elements of both. As you say, Alex, Ukraine stated: "On 28 November 2018, Ukraine furthermore argued that its rights under the LOSC had been violated and that ʻall detained Ukrainian servicemen are protected by the norms of international humanitarian law, in particular the Geneva Convention Relative to the Treatment of Prisoners of War, 1949." Certainly, I believe that states - including Russia and Ukraine should be consistent in their words and decriptions of the rules they are applying, and then act consistently with them.

James Kraska says

December 4, 2018

Russia is clearly violating the rights of third party flag states by hampering their right to transit at least in innocent passage, if not transit passage. I am undecided on the legitimacy of the internal waters claim, but the presumption is that the Sea of Azov is not under historic title and the test for determining that status is anotoriously difficult hurdle to overcome.

Arron N. Honniball says

December 5, 2018

Thank you Professor Kraska for a thought provoking and timely piece. As Professor Proelss has already covered the Ukrainian statements, I consider it may be worth examining the official position of Russia which may not be captured by news articles. The statements of the FSB (hyperlinked at the bottom of this comment) are particularly enlightening for the question of whether innocent passage was exercised and what coastal state rights are available beyond UNCLOS, Art. 30 requests concerning warships not exercising innocent passage. Of course, I am reliant upon google translate so any Russian speaking readers are welcome to correct errors below.
While I do not wish to take any position on the accuracy of the facts by either side, the FSB statement provides further insight on what exactly the Ukraine violation of UNCLOS, Article 19 you mention purportedly were. The vessels are said to be combat ready, with artillery uncovered and raised at an angle of 45 degrees towards the Russian vessels. Whether this could be interpreted at prejudicial to the peace, good order or security of the coastal State and therefore not be an exercise of innocent passage is open to debate. Given the tensions, comparison to the Corfu Channel case might nonetheless provide for passage?

Secondly, the FSB statement refers to UNCLOS, Article 25(3) whereby a coastal state may temporarily suspend innocent passage within an area of its territorial sea if duly published. The communication from the Russian commander says they were previously informed, although I have not checked if this was duly published. A violation was purportedly permitted upon entry into this suspended area.

Thirdly, on the issue of UNCLOS, Article 21 it appears Russia raises this in connection with UNCLOS, Article 22 whereby sea lanes and traffic separation schemes may be established in the territorial sea. I’m not sure about the pilotage issue you raise as the link was not working, so if you have another stating this was at issue in the dispute that would be very helpful. It does however appear from these statements that the issue was the failure to follow the Russian established permit procedure. Order No. 313 of the Ministry of Transport of the Russian Federation (2015) provides “In the seaport and on the approaches to it, a permitting procedure for the movement and anchorage of ships operates” (Article 20) whereby “Information about the vessel’s approach to receiving buoys (Varzovsky buoy when passing a ship in transit from the Sea of Azov or to buoy N 1 KEK when a ship passes from the Black Sea) the ship’s captain or ship’s agent is sent to the seaport captain (copy in the VTS) 48 hours before the approach, re-transmit 24 hours and finally clarify four hours before the approach” (Article 38). By not providing the advance notification, passage in the Kerch-Yenikalya canal was prohibited.

The issue of transit passage is not discussed for obvious reasons. However, surely by analogy the position they would take in the first and third arguments would be similar - albeit based upon UNCLOS, Articles 39(1), 41 and 42. The second argument would fall away as no suspension is allowed (UNCLOS, Article 44, 45). It is worth noting the position, as of 21 November 2018, remains that the Sea of Azov is internal waters and no right of transit passage is applicable

Finally, if the vessels are exercising innocent passage the position is rather clear. However, if we assume that they were indeed not exercising innocent passage I’m curious what options are left to a coastal state if the Russian statement of facts is taken? According the FSB, radio requests to the Ukrainian vessels to leave the (disputed) territorial sea were made (in compliance with UNCLOS, Article 30). It then appears to have gone downhill, with requests to stop, a blockade, ‘preventative’ fire or ‘warning’ shots, more requests, the use of weapons resulting in injuries and finally vessel detention. The end result appears rather excessive, but it appear difficult to pinpoint the exact point at which steps taken by a coastal state to ensure a sovereign immune vessel to leave have become excessive.

FSB sources :,

Antigone says

December 14, 2018

Thanks for this very interesting piece and especially the equivalently thought provoking answer by Mr. Proelss.

Despite perceiving myself as following the events quite closely, I just accidentally got to know, that the ECtHR granted provisional measures regarding the right to life of the Ukrainian sailors. Just wanted to leave that case here for general interest.,%22sort%22:%5B%22kpdate%20Descending%22%5D%7D