Ukraine denies attack on Russian ships in Black Sea

Kyiv did not attack and will not attack civilian vessels or any other civilian objects in the Black Sea, says a senior Ukrainian presidential adviser, calling Russian statements 'fictitious'.

Russia's defence ministry said on Tuesday it had thwarted attacks by Ukrainian sea drones on its navy and civilian ships in the Black Sea.

Russia was facing attacks on several fronts, with a drone strike hitting a high-rise building in Moscow's business district that houses three Russian government ministries for the second time in three days.

"During the night the armed forces of Ukraine made an unsuccessful attempt to attack the Sergei Kotov and Vasiliy Bykov patrol ships of the Black Sea fleet with three unmanned sea boats," the defence ministry said in a statement on Tuesday.

It said the two ships were controlling shipping 340 km southwest of Sevastopol and would continue to perform their duties.

Later, in its daily briefing, the ministry said navy ships had destroyed three more sea drones targeting civilian vessels.

"During the night, the Kyiv regime attempted a terrorist attack with three semi-submersible unmanned boats on Russian civilian transport vessels heading towards the Bosphorus Strait in the southwestern part of the Black Sea," the ministry said.

"Undoubtedly, such statements by Russian officials are fictitious and do not contain even a shred of truth," Mykhailo Podolyak, adviser to President Volodymyr Zelenskiy, told Reuters.

"Ukraine has not attacked, is not attacking and will not attack civilian vessels, nor any other civilian objects."

Russia has said it would treat any ships leaving or entering Ukrainian ports as valid targets after the expiration of a United Nations-backed deal last month which had allowed for exports of Ukrainian grain via the Black Sea.

Tuesday's incident was the first clash of Ukrainian sea drones with the Russian navy in deep sea. Kyiv has previously used drones to target Russia's navy base in Crimea and the bridge that Russia has built to the peninsula.

Russia annexed the Crimean peninsula from Ukraine in 2014. Kyiv has demanded that Moscow hand it back.