Russia repelled an attack by naval drones on its Black Sea fleet stationed in the Crimean port of Sevastopol in the early hours of Monday, Russia's defence ministry said.
Sevastopol, which is on the Crimean peninsula that Russia annexed from Ukraine in 2014, has come under repeated air attack since Russia sent troops into Ukraine last February. Russian officials have blamed the attacks on Ukraine.
"At about 3.30 a.m. (0030 GMT), the Kyiv regime tried to attack the base of the Black Sea Fleet in Sevastopol with three unmanned high-speed boats," the ministry said in a statement.
Russia destroyed all three of the naval drones, suffering no casualties or losses in the process, it said.
Reuters was unable to verify the claim.
Residents in the city told Reuters they were concerned about the wave of drone attacks they faced living in Sevastopol, but some had adjusted to the threats.
"When the drones attack, it wakes you up, of course. There's nowhere you can sleep peacefully, the house shakes. You worry for your children," Elena Kudrenko said on Monday.
"But we are confident the anti-missile system works well and that Sevastopol is well protected," she added, standing on the waterside near the city's ferry port.
"We've got used to the constant noise and constant (military) drills. We barely notice it any more," another resident, Olga Lonshakova, said.
There was no immediate reaction from Ukraine. Kyiv almost never publicly claims responsibility for attacks inside Russia and on Russian-controlled territory in Ukraine.
Russia annexed Sevastopol, along with the rest of the Crimean peninsula which juts into the Black Sea, in 2014 but it is internationally recognised as part of Ukraine. The city has been a major base for Russia's navy for more than two centuries.
Separately on Monday, a local Russian official said a Ukrainian-made drone packed with explosives had been found crashed in a forest in the Moscow region. No casualties were reported.
Last month three people were injured and apartment blocks were damaged when Russia said it downed a Ukrainian drone south of the Russian capital.
(Reporting by Reuters; Writing by Jake Cordell and Lidia Kelly; editing by Stephen Coates, Gareth Jones and Mark Heinrich)