A Russian navy ship collided with another vessel off the Turkish coast in the Black Sea Thursday, Russias defence ministry said, adding that its crew was trying to keep it afloat.

The research ship Liman"sustained a hull breach due to a collision" with the ship Ashot-7, 40 kilometres (25 miles) northwest of the Bosphorus Strait, the ministry said in a statement carried by Russian agencies.

The statement said the crew was not harmed but is "fighting to keep the ship" afloat and that other Russian navy ships and a plane have been dispatched to the scene.

The Russian military said it is trying to identify the owner of the Ashot-7 ship.

In February, military sources told Russian media that it would be observing NATO's Sea Shield exercise in the Black Sea.