Ukraine’s domestic security service, the SBU, said Monday that it had carried out an attack on a Russian submarine in the Black Sea port of Novorossiysk, causing critical damage to the vessel and effectively disabling it.

Ukraine's internal security agency said the attack damaged and disabled a Russian Kilo-class submarine in the port city of Novorossiysk.

As it tried to demonstrate its continuing ability to fight, Ukraine said it had used drones to inflict serious damage on a Russian Kilo-class submarine at a Black Sea port.

The Security Service of Ukraine reported that it had struck an Improved Kilo-class submarine at the Russian naval base at Novorossiysk. The attack was carried out with a “Sub Sea Baby” drone.

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.

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 nuclear reactor of the fourth Suffren-class nuclear-powered attack submarine (SSN), De Grasse (S638), was fired up for the first time.

The attack with Ukrainian-made "Sub Sea Baby" drones hit the submarine in the port of Novorossiysk where Russia has rebased ‍many of its Black Sea naval vessels ​to put them out of reach of Ukrainian strikes, the Security Service of Ukraine (SBU) said.

Submarine builder General Dynamics Electric Boat delivered a Virginia-class attack boat to the U.S. Navy on Monday, the service announced. The future USS Idaho (SSN-799) is the second attack boat the Navy has received this year,