Ukraine claimed that it had "for the first time" used an unmanned underwater vehicle to disable the mobility of a Russian submarine, but Russia denied it

Ukraine said it had for the first time used an unmanned underwater vehicle to hit a Russian missile submarine moored at a Black Sea naval base, causing the submarine to explode, catch fire and lose its operational capability. Moscow denies that the attack has caused any losses.

According to reports from Reuters and Xinhua News Agency, the National Security Service of Ukraine posted on social media on Monday (December 15) that the National Security Service and the Navy carried out joint special operations against the Russian port of Novorossiysk. The unmanned submersible "Sub Sea Baby" made in Ukraine hit a Russian Navy submarine of Type 636.3 "Warsaw Woman" class (referred to as Kilo-class by NATO).

The submarine moored at the port is equipped with Kalibr cruise missiles that can be used to strike the Ukrainian interior. A video released by Ukraine's National Security Service shows a violent explosion on the water surface near a pier where a submarine and other vessels were moored. Reuters confirmed the shooting location of the video based on the layout of the port and the location of the wharf.

The Ukrainian National Security Service said that due to the previous successful special operations of the Ukrainian unmanned surface vessel "Haiying", this type 636.3 submarine was forced to anchor at the port of Novorossiysk.

Ukrainian President's advisor Kameshin posted on X that this was the first time in history that an underwater vehicle had caused a submarine to lose its operational capability. Several hours later, the Russian Black Sea Fleet flatly denied this claim.

The Russian state news agency quoted the Black Sea Fleet as saying: "The vessels and submarines of the Black Sea Fleet stationed in the Gulf of the Novorossiysk Naval base have not been damaged by sabotage activities. The crew members are unharmed and are currently on normal duty."

The Type 636.3 diesel-electric submarine is an improved third-generation conventional submarine of the Kilo-class. This submarine is 73.8 meters long and 9.9 meters wide, with a speed of 20 knots, a maximum diving depth of 300 meters, a self-endurance of 45 days, a crew of 52, and a submerged displacement of 4,000 tons. Its combat effectiveness has been significantly enhanced compared to previous models.

The Port of Novorossiysk is located on the eastern coast of the Black Sea in the Krasnodar Krai in southern Russia and is a key logistics supply facility for Russia in the Black Sea.