Russia's navy on Friday destroyed an uncrewed Ukrainian navy vessel heading towards Crimea, the defence ministry said.

"At about 08:00 Moscow time, an unmanned Ukrainian navy boat was discovered in the western Black Sea heading towards the Crimean Peninsula," the defence ministry said.

"The discovered target was destroyed."

Russia annexed Crimea from Ukraine in 2014.

Reuters was unable to immediately verify battlefield reports from either side. (Reporting by Reuters; editing by Guy Faulconbridge)