Ukraine’s SBU said it used unmanned underwater drones to strike a Russian Kilo-class submarine in Novorossiysk, releasing video of a large explosion though independent verification is lacking. Russia denied any damage, calling the sabotage attempt unsuccessful. The SBU described the sub as a costly, low-signature platform capable of launching Kalibr cruise missiles and said sanctions have likely increased replacement costs. The incident coincided with Berlin talks on robust security guarantees, a potential multinational force and a U.S.-led ceasefire monitoring mechanism.
Ukraine Says Underwater Drones Critically Damaged Russian Submarine at Novorossiysk — SBU Releases Video
Ukraine’s domestic security service (SBU) announced on Monday that it carried out an operation using unmanned underwater vehicles that struck a Russian Kilo-class submarine moored in the Black Sea port of Novorossiysk, inflicting what the agency described as critical damage and effectively putting the vessel out of action.
In its statement the SBU said the attack employed underwater “Sub Sea Baby” drones — marking, the agency said, the first time Ukraine has used this type of drone to target a submarine. The SBU released video it said showed a large explosion at the port.
“As a result of the explosion, the submarine suffered critical damage and was effectively put out of action,” the SBU said. Independent verification of the claim was not available.
Russian authorities acknowledged an attempted Ukrainian operation but insisted it failed and that no ships or submarines were harmed. State media quoted Alexei Rulev, head of the Black Sea Fleet press service, saying the sabotage attempt with an unmanned underwater vehicle did not achieve its objectives and denying Ukrainian reports that a submarine had been destroyed at the Novorossiysk naval base.
About the Submarine and The Claim
The SBU identified the target as a Kilo-class diesel-electric submarine, a platform known for its low acoustic signature and often nicknamed the “Black Hole.” The agency noted the class can launch Kalibr cruise missiles and said one such sub can fire up to four Kalibrs at a time. The SBU estimated the value of a Kilo-class boat at roughly $400 million and suggested international sanctions could raise the replacement cost to about $500 million because of restricted access to key components.
The SBU also said the vessel had remained in Novorossiysk after earlier Ukrainian sea-drone operations compelled Moscow to move many ships and submarines out of Sevastopol Bay in occupied Crimea.
Diplomacy and Timing
The announcement came amid intensive diplomacy aimed at ending Russia’s war in Ukraine. It was made shortly after a second day of talks between U.S. and Ukrainian delegates in Berlin.
At a news conference in Berlin, President Volodymyr Zelensky said Kyiv must be “absolutely sure” how any security guarantees would work before accepting terms that affect the front line. Speaking alongside German Chancellor Friedrich Merz, Zelensky emphasized that monitoring a ceasefire must be central to any guarantees, asking who would carry out monitoring and what sanctions would apply if monitoring missions were disrupted.
Merz said the United States had offered “significant” material and legal guarantees in the talks, without providing further details. European leaders later issued a joint statement backing a European-led multinational force, supported by the United States, to help rebuild Ukraine’s forces, secure airspace, and support safer seas — including operations inside Ukraine. They also proposed a U.S.-led ceasefire monitoring and verification mechanism with international participation.
In a social media post, Zelensky noted meetings with U.S. representatives, including Steve Witkoff, described by some as a special envoy, and Jared Kushner. He said elements he considered “destructive” in previous peace proposals had been removed from newer drafts and reiterated that territorial issues with Russia must be discussed openly.
Reporting note: The SBU released video and an official statement; independent verification of damage to the submarine was not available at the time of publication. Daria Tarasova-Markina and Hira Humayun contributed to reporting.
