On December 15th, the Security Service of Ukraine (SBU) reported that it had struck an Improved Kilo-class submarine at the Russian naval base at Novorossiysk. The attack was reportedly a joint operation between the 13th Main Directorate of Military Counterintelligence of the SBU and the Ukrainian Naval Forces and made use of a “Sub Sea Baby” drone.
The SBU also released a video of the attack (see below) showing how the drone struck the stern of an Improved Kilo-class submarine moored at the far end of the submarine pen inside the naval base. So far there is no independent verification if the submarine was sunk in port. Available images