Russian President Vladimir Putin warned Wednesday that Moscow will seek to extend its gains in Ukraine if Kyiv and its Western allies reject the Kremlin’s demands in peace talks.

Ukraine’s domestic security service, the SBU, said it struck a Russian submarine in the Black Sea port of Novorossiysk, Russia, disabling it, in a first attack of its kind. Russia acknowledged the attack but said no ships or submarines were damaged.

Ukrainian officials said the strike hit a key Russian naval asset at Novorossiysk, dealing a major blow to Moscow's Black Sea Fleet and complicating efforts to repair or replace the vessel.

Alexander Kamyshin, an advisor to President Volodymyr Zelensky, wrote on X that it was the first time in history that an underwater drone had neutralised a submarine.