Ukraine has claimed it carried out the world’s first successful underwater drone attack on a Russian submarine, saying the strike disabled a missile-carrying Kilo-class vessel at the Black Sea port of Novorossiysk.

According to Ukrainian officials, the operation was conducted by the Security Service of Ukraine (SBU) using domestically developed underwater drones known as “Sub Sea Baby.”

The drones reportedly struck the submarine while it was docked at the port, which has become Russia’s most important remaining naval base in the Black Sea after several ships were relocated from Crimea.

Footage released by the SBU showed a powerful explosion erupting from beneath the water near a pier where submarines and other vessels were moored. Reuters verified the location of the footage by matching the port’s layout and pier structures.

An adviser to President Volodymyr Zelensky stated in a social media post that this marked the first time in history that an underwater drone had neutralised a submarine.

However, Russia later rejected the claim. Russia’s Black Sea Fleet said that none of the ships or submarines stationed at Novorossiysk were damaged and that all crews remained on active duty.

Ukrainian authorities said the targeted vessel was a Project 636.3 Varshavyanka-class submarine, known by NATO as the Kilo class.

Video Credits: SBU/YouTube 

The submarine is capable of carrying at least four Kalibr cruise missiles, which Ukraine says Russia has frequently used in strikes that caused significant damage to Ukraine’s power infrastructure.

The SBU stated that the submarine suffered critical damage and was effectively put out of action. Ukrainian officials added that repairing such a vessel would be difficult, as repairs would need to be carried out above water, leaving it exposed to further attacks.

A Ukrainian navy spokesperson described the strike as a shift in naval warfare during the conflict, saying that submarines are among the hardest targets to hit.

The spokesperson also said Russia had four submarines stationed in Novorossiysk, three of which are capable of launching Kalibr missiles, and claimed that one of them had now been lost.

Ukraine has relied heavily on sea drones and missile strikes as it no longer has a traditional naval fleet. These tactics have previously forced Russia to move several warships and submarines away from Sevastopol in Crimea to ports farther from Ukrainian-controlled waters.

The SBU said the operation was conducted jointly by its military counterintelligence unit and the Naval Forces of Ukraine.

Ukrainian officials estimated the cost of a Varshavyanka-class submarine at around $400 million, adding that international sanctions could raise the cost of replacing such a vessel to as much as $500 million.

The reported strike comes at a sensitive time, as US-brokered peace negotiations continue. Ukrainian officials have sought to demonstrate their ability to damage Russian military assets, amid concerns that Kyiv could face pressure to accept unfavourable settlement terms.

References: SBU, Reuters