This was reported by the British Ministry of Defence on Twitter.
British military intelligence notes that on March 22, at least 3 surface and 1 aircraft drones attempted to strike the Russian naval base in Sevastopol, Crimea.
Open-source reports indicate that one maritime drone was allegedly stopped by defense booms, while the other 2 were destroyed in the harbor. Russian officials said that no Russian vessels were damaged.
"A previous USV attack on Sevastopol on 29 October 2022 reportedly damaged the minesweeper Ivan Golubets and the frigate Admiral Makarov. Even though the new attacks likely failed to damage any military assets, the USV threat likely continues to constrain operations of Russia’s Black Sea Fleet," the British intelligence concluded.
On March 22, Russian occupation authorities of Sevastopol announced an attack by naval drones.