UKRAINE has claimed Russia has rammed one of its boats off the coast of Crimea, amid rising naval tensions.

A Ukrainian navy statement says the “openly aggressive actions” happened as three of its vessels sailed to Mariupol in the Sea of Azov.

The tug, named Yana Kapu, allegedly suffered damage to its engine, guard rail and outer shell.

But Russia said the ships were in its waters, and accused the Ukrainians of “provocative actions”.

The incident took place as two Ukrainian navy artillery boats and a tugboat were transiting from Odessa on the Black Sea to Mariupol in the Sea of Azov, via the Kerch Strait, a narrow passage between Crimea and the Russian mainland.

The Sea of Azov lies east of the Crimean peninsula, which was annexed by Russia in 2014, and south of regions held by pro-Russian separatists.

“Russian coast guard vessels (...) carried out openly aggressive actions against Ukrainian navy ships” during the transit, the Ukrainian navy statement said.

It said a Russian coast guard ship damaged the tugboat’s engine, hull, side railing and a lifeboat.

The statement added that Russia had been informed in advance about the planned transit.

Russia’s Federal Security Service (FSB) told Russian news agencies that the Ukrainian ships held their course and violated Russian territorial waters, which were temporarily closed.

“Their goal is clear,” an FSB statement said, “to create a conflict situation in the region”.

The statement did not mention ramming a Ukrainian tugboat.

The Interfax news agency reported later that Russia has since closed the passage to civilian traffic, citing a local port authority, due to heightened security concerns.

Though a 2003 treaty designates the Kerch Strait and Sea of Azov as shared territorial waters, Russia has been asserting greater control over the passage since 2015.

According to the Ukrainian navy, “the occupiers’ dispatch service refuses to ensure the right to freedom of navigation, guaranteed by international agreements”.