Ukraine demanded the release of its sailors and more sanctions against Moscow on Monday after the Russian navy fired on and seized three Ukrainian ships off the coast of Crimea.
In a sharp escalation of tensions between the ex-Soviet neighbours, Russia boarded and seized the three ships on Sunday, accusing them of illegally entering Russian waters in the Sea of Azov.
The confrontation at sea has raised fears of a wider military escalation, and the UN Security Council was to hold an emergency session late on Monday to consider a response. Nato also called an emergency meeting on the incident.
Ukraine’s military was on high alert and parliament was to vote on Monday on a request from President Petro Poroshenko to impose martial law for 60 days.
In a statement early on Monday, Ukraine’s foreign ministry denounced “another act of armed aggression” by Russia.
It demanded “the return of the captured navy ships” and urged its Western allies “to take all necessary measures to deter the aggressor . . . by applying new and strengthening existing sanctions”.
Moscow blamed Kiev for the incident, with Foreign Minister Sergei Lavrov accusing Ukraine of a planned provocation and of using “dangerous methods” that put ships in the area at risk.
Moscow summoned a senior Ukrainian diplomat to the foreign ministry to complain over the incident.
The crisis unfolded as two small Ukrainian warships and a tugboat were heading through the Kerch Strait, a waterway that gives access to the Sea of Azov from the Black Sea and which is used by both Ukraine and Russia.
Ukraine said a Russian border guard vessel rammed the tugboat and then fired on the ships, immobilising all three. It said the Kerch Strait was blocked by a tanker and that Russian military aircraft were flying over the area.
Russia’s FSB security service, which oversees border forces, confirmed weapons had been fired and the vessels seized, accusing the Ukrainian ships of “violating the Russian border”.
Ukraine said six of its servicemen were injured, two seriously. The FSB said only three had suffered non-life threatening injuries and were given medical treatment.
Russian news agencies quoted port officials in Crimea as saying the strait was reopened to traffic early on Monday.
Tensions over sea access
The confrontation is a dangerous development in the long-running conflict pitting Ukraine against Moscow and Russian-backed rebels in the east of the country.
Tensions have been building over the Kerch Strait, where Russia has built a new bridge that gives it a land connection to Crimea, annexed by Moscow in 2014.
Kiev has accused Moscow of blocking access for Ukrainian ships though the strait, the only way in and out of the Sea of Azov to the Black Sea.
In recent months both sides had deployed more naval and border vessels to the area.
Kiev and the West have also accused Moscow of deliberately blocking ships from accessing the Ukrainian port of Mariupol, which has vital access to heavy industry in the eastern part of the country.
Mariupol is close to the region controlled by Russian-backed separatists in a conflict that has caused at least 10,000 deaths since 2014.
The European Union and NATO on Sunday urged restraint, with the Western military alliance calling on Russia “to ensure unhindered access to Ukrainian ports in the Azov Sea, in accordance with international law”.
Black Sea power Turkey expressed concern on Monday, while Germany said a Russian blockade of the Sea of Azov was “unacceptable”.