With an underwater drone, the Ukrainian Security Service destroyed an Improved Kilo-class (Varshavyanka) sub in the port of Novorossiisk. A fleet of six subs of the same class is planned built for the Northern Fleet.

The Russian submarine was allegedly carrying Kalibr cruise missiles, which Russia has used in devastating strikes on critical infrastructure and military targets across Ukraine. The SBU said the submarine was “put out of action” as a result of the blast. The FT could not independently verify the claim.

A British naval supply ship with an on-board helicopter was deployed to track the stealthy Kilo-class submarine Krasnodar, the Royal Navy said.