(CNN) — The Ukrainian military said Sunday that Russian boats had opened fire on and seized three of its ships near Crimea, escalating a standoff over the Kerch Strait, a waterway that links the Azov Sea with the Black Sea.
In a statement, the Ukrainian Ministry of Defense said the small gunboats Berdyansk and Nikopol and the tugboat Yana Kapu were attacked.
Six of its sailors were injured in the incident, Ukraine’s navy said, adding the tugboat and the Berdyansk were disabled by Russian forces and were being towed away by the Russian navy. The undamaged Nikopol also is under Russian control, Ukraine said.
Earlier, Russian authorities closed off the Kerch Strait amid the confrontation with the Ukrainian naval vessels, Russian state news agencies and the Ukrainian military said.
Ukraine and Russia offered conflicting accounts of the incident at sea.
Russia says Ukraine ships trespassed
Russian state news agency RIA-Novosti, citing Russia’s Federal Security Service, or FSB, said the three vessels of the Ukrainian navy had reversed course away from Kerch Strait.
The FSB’s Border Service in Crimea reported that three Ukrainian warships had illegally entered Russia’s territorial waters, and were carrying out dangerous maneuvers, according to Russian state news agency TASS.
According to RIA-Novosti, the FSB blamed Kiev for provocation in the waters of the Black Sea.
The Ukrainian navy said Russian border patrol vessels “carried out openly aggressive action” against the Ukrainian ships.
The office of Ukrainian President Petro Poroshenko described the Russian action against the Ukrainian navy ships as “an act of aggression aimed at deliberately escalating the situation in the waters of the Sea of Azov and the Kerch Strait,” and called for international condemnation of Moscow and the imposition of new sanctions.
Ukraine leader says he wants martial law
Poroshenko convened a military cabinet emergency meeting and later tweeted he would appeal to Parliament to declare martial law. “There are no red lines” for Russia, he said. “We consider such actions categorically unacceptable. And this aggression has already led to consequences.”
The Azov Sea is an important economic lifeline for Ukraine, as it links the port city of Mariupol with the Black Sea. Both Ukraine and Russia share the Azov Sea. According to TASS, a 2003 treaty confirms the Azov Sea and the Kerch Strait as domestic waters of Russia and Ukraine.
The Kerch Strait is the only point of access to the Azov Sea from the south. It’s a shallow, narrow stretch of water just two to three miles (3.2 to 4.8 kilometers) wide at one point near the Chuska landspit.
In a statement to CNN, NATO spokesperson Oana Lungescu said NATO “fully supports Ukraine’s sovereignty and its territorial integrity” and is calling on Russia “to ensure unhindered access to Ukrainian ports in the Azov Sea.” The European Union echoed the latter sentiment.
“NATO is closely monitoring developments in the Azov Sea and the Kerch Strait, and we are in contact with the Ukrainian authorities. We call for restraint and de-escalation,” the statement said.
An emergency United Nations Security Council meeting has been called for Monday morning, outgoing US Ambassador to the United Nations Nikki Haley posted Sunday evening on social media.
Ukraine and the United States have been accusing Russia of interfering with international shipping in and out of the Kerch Strait for some months now.
Russia and Ukraine have also been locked in conflict since the annexation of the Black Sea peninsula of Crimea by Russia in 2014, and a war with Russian-backed separatists in the country’s east has claimed more than 10,000 lives. The incident at sea raises new tensions between the two countries.
Russian state media has reported the confrontation is a provocation orchestrated by Ukraine and others in America to disrupt the forthcoming meeting between Russian President Vladimir Putin and President Donald Trump at the G20 Buenos Aires summit this week.
Russia has backed separatists in Ukraine’s eastern Donbas region, and earlier this year, Russia solidified its hold over Crimea, opening a road linking Russia’s Krasnodar region with the Crimean Peninsula.
The international community has largely not recognized Russia’s annexation of the Black Sea peninsula of Crimea from Ukraine. According to TASS, a 2003 treaty confirms the Azov Sea and the Kerch Strait as domestic waters of Russia and Ukraine.