Russian nuclear-armed submarine reports 'explosion hazard' due to fuel leak in the Mediterranean

A Russian submarine capable of carrying nuclear missiles declared an explosion hazard after suffering a fuel leak in the Mediterranean, according to reports circulating on Russian social-media channels. The Black Sea Fleet submarine Novorossiysk, a Kilo-class diesel-electric attack boat, was described by the Telegram channel VChK-OGPU as experiencing serious technical problems and issuing an urgent warning. The channel cited an unnamed source and did not provide verifiable confirmation from a formal spokesman. It was unclear exactly where in the Mediterranean the vessel was located at the time of the report. The submarine had been observed by Royal Navy vessels earlier in the year during its passage from the North Sea into the English Channel and on to the Mediterranean.

The channel’s account said damage in the fuel system was causing fuel to leak directly into the submarine’s hold. It asserted there were no spare parts for repairs and no qualified specialists aboard the vessel, and that the crew was reportedly unable to fix the malfunctions. The statement warned that the accumulated fuel in the hold posed an explosive hazard and suggested the crew had little option but to pump the hold directly into the sea. There has been no official statement confirming that the submarine is in distress.

The Novorossiysk is a Black Sea Fleet vessel, a 242-foot (approximately 74 meters) diesel-electric attack submarine designed to carry Kalibr missiles, though on the current Mediterranean mission it was not believed to be armed with nuclear weapons. The submarine’s crew is reported to number 52, and the boat can stay submerged for up to 45 days at a time. The vessel’s presence in the North Sea and English Channel was noted by Royal Navy observers in July, when a patrol ship and accompanying aircraft tracked the submarine as it moved westward toward the Atlantic, with subsequent sightings placing it in the Mediterranean via Gibraltar in early August.

British authorities have monitored the surfaced submarine as part of ongoing efforts to safeguard British waters. HMS Mersey, a Royal Navy patrol ship based in Portsmouth, along with a Wildcat helicopter from 815 Naval Air Squadron and a Merlin aircraft from 824 Naval Air Squadron, tracked the Novorossiysk during its North Sea and Channel transit. The Royal Navy has repeatedly scrambled Mersey to monitor Russian vessels in British waters in recent months, with the service describing the patrols as part of broader vigilance over the so-called shadow fleet of Russian warships and security vessels that authorities fear could threaten critical underwater infrastructure.

The broader context for such monitoring includes concerns that Russia could exploit merchant vessels, spy ships, or other assets to disrupt submarine cables or other offshore infrastructure. In parliament, Defense Secretary John Healey noted a separate incident in which a Royal Navy nuclear submarine surfaced near a Russian counterpart in November, citing it as an example of ongoing operational vigilance in the region. Analysts point to the steady tempo of anti-submarine patrols and the emphasis on underwater-domain security as part of a long-running effort to deter malign activity in European waters and the approaches to NATO allies.

Russian security-channel leaks are often difficult to verify independently, and Channel VChK-OGPU is known for releasing items tied to the Russian security services and law-enforcement communities. Ukraine has claimed that a sister submarine, Rostov-on-Don, was sunk in August 2024, a claim that has circulated in various outlets but remains disputed in many official circles. The current report about the Novorossiysk underscores how developments involving Russian naval assets in and around the Mediterranean continue to attract scrutiny from Western observers, even as no formal confirmation has emerged from Moscow.

Officials in Moscow have not commented publicly on the specific fuel-leak alert or any operational implications for the Novorossiysk. The absence of an official statement has left a gap that Western maritime authorities and defense ministries have attempted to fill with routine tracking data and historical context about Russian naval activity in the region.