The Russian navy "repelled" a drone attack on the port of Sevastopol in Moscow-annexed Crimea early on Wednesday, the Kremlin-backed governor of the city said.

The attack came just four days after President Vladimir Putin made a surprise visit to Sevastopol.

He said military personnel had shot at the drones with "small arms" and that "air defense was also working."

Razvozhayev added there were no casualties and claimed no ships had been damaged, but said that the explosions blew out windows in nearby buildings.

A day earlier Kyiv said Russian cruise missiles being transported by train were destroyed in a blast in Crimea but denied responsibility for the incident.

In October, Russia's Black Sea Fleet was hit by a major drone attack that the Kremlin blamed on Ukraine.