Russian nuclear-capable submarine declares explosive-hazard alert after fuel leak in the Mediterranean

A Russian submarine capable of carrying nuclear missiles has declared an "explosion hazard" alert after suffering a fuel leak in the Mediterranean, according to a Russian Telegram channel. The Black Sea Fleet boat Novorossiysk, a diesel-electric attack submarine, is described as experiencing serious technical problems and may be forced to pump fuel from the hold directly into the sea. There is no official confirmation of trouble from Moscow, and the submarine’s exact location in the Mediterranean was not disclosed.

Novorossiysk is a 242-foot (about 74 meters) Kilo-class submarine with a crew of 52. It is designed to carry nuclear-capable Kalibr missiles, though officials cited in the report said it is unlikely to be arming such missiles on the current mission. The vessel has drawn attention in recent weeks after being tracked by Western forces during its passage from the North Sea and English Channel toward the Mediterranean this summer. It was observed by Royal Navy assets in July as it moved through the North Sea and the English Channel, and in August was seen entering the Mediterranean via the Strait of Gibraltar.

There has been no official statement from Moscow about the submarine’s status. The Telegram channel VChK-OGPU, which aggregates leaks from Russian security services, quoted an unnamed source saying fuel-system damage left the hold with a hazardous amount of fuel and that spare parts and qualified technicians were unavailable aboard. The report suggested that the crew might have no choice but to pump the fuel directly into the sea to reduce the risk of a more catastrophic failure, though it cautioned that the claim could not be independently verified.

Royal Navy forces have actively tracked the surfaced or near-surface Novorossiysk as it traversed northern waters in recent months. HMS Mersey, a patrol ship based in Portsmouth, was scrambled to intercept the submarine’s movement as it was observed with support from a Wildcat helicopter from 815 Naval Air Squadron and a Merlin aircraft from 824 Naval Air Squadron, all using advanced sensors to monitor the vessel and its accompanying support craft. The British deployment marked the sixth time Mersey had been scrambled in about three months to monitor Russian naval movements in or near British waters. In a related context, Defense Secretary John Healey told Parliament that the United Kingdom continues to monitor Russia’s so-called "shadow fleet" of merchant ships and security- service-linked assets as part of ongoing efforts to safeguard underwater infrastructure and national waters.

The episode comes amid broader concern in Western capitals about Russia’s maritime activity and its potential risk to critical undersea infrastructure in and around Europe. Observers note that while the Novorossiysk is a Black Sea Fleet vessel, it has not been publicly tied to active combat operations in Ukraine. The timing and specifics of any current mission remain unclear, and officials have urged caution until official statements are issued by Moscow.

Until the situation is formally clarified, the British and allied maritime and intelligence communities are continuing to monitor the submarine and its surroundings as part of routine defense and deterrence patrols in European waters. The Mediterranean operation underscores the ongoing exchange of intelligence reporting and the high level of vigilance that characterizes Western responses to Russian naval movements near Western seaboards.