Russia's defense ministry says Russian forces have destroyed Ukrainian unmanned speedboats that tried to attack a ship of its Black Sea Fleet.
A spokesperson for the ministry said three fast boats of the Ukrainian military launched the attack, but were knocked out 140 kilometers northeast of the Bosphorus Strait.
The ministry released a video that it claims shows their destruction.
The ministry said the targeted vessel was on duty to protect pipelines that send natural gas from Russia to Turkey. It said the drones mounted the attack in Turkey's exclusive economic zone.
Earlier this month, Russia and Ukraine agreed on an extension of a deal that allows Ukrainian grain to be exported through the Black Sea.
But observers say the alleged attack by Ukraine may affect future negotiations on the issue.