Ukraine claims it has carried out the first successful combat strike by an underwater drone against a submarine, damaging a Russian Kilo-class boat in the Black Sea port of Novorossiysk and potentially removing a key cruise missile launch platform from the war.

The Ukrainian military says it has blown up a $400m Russian submarine in an unprecedented attack on the Russian navy’s most important remaining Black Sea base located in Novorossiysk. The strike marks the first time an underwater drone has neutralised a submarine, according to President Volodymyr Zelensky ’s advisor Alexander Kamyshin.

"Varshavianka" has lost her fighting ability and cannot sail on her own.

The drones were “neutralized,” daily Liberation reported, with the newspaper saying the usual procedure involves jamming.

EADaily, . Sub Sea Baby underwater drones struck the Varshavyanka submarine in the port of Novorossiysk, launching Kalibr missiles at targets on the Ukraine. This was stated by the SBU in its telegram channel.

The Île Longue facility houses France's four nuclear ballistic missile submarines and provides maintenance for the vessels that form the basis of the country's nuclear deterrent.

French officials are investigating an illegal drone overflight of the Atlantic coast base for France's nuclear-armed submarines.