RUSSIA said Ukraine made unsuccessful attack a Russian naval ship with six high-speed drone boats, Reuters reports.

The Russian target vessel was patrolling natural gas pipelines in the Black Sea at the time of the attack, said the report.

Russia said Ukraine attacked 300 kilometres south-east of Sevastopol, the headquarters of Russia's Black Sea fleet.

"The Black Sea Fleet ship Priazovye continues to carry out its assigned tasks," the defence ministry said.