The Russian cargo ship Ursa Major which sank in the Mediterranean on the night of December 23, 2024 after an explosion ripped through its engine room while heading south of Mallorca may have been attacked by a submarine, according to a report by the Spanish newspaper La Verdad, citing details of an official investigation.
According to the paper’s sources, officials suspect the ship was targeted by the forces of a Western country in order to prevent the delivery to North Korea of two nuclear reactors allegedly being transported aboard the vessel. The vessel, built in 2009, was controlled by Oboronlogistika, a company that is part of the Russian Defence Ministry’s military construction operations, which had previously said it was en route to the Russian far eastern port of Vladivostok with two giant port cranes lashed to its deck.
Russia’s embassy in Spain was cited by the state RIA news agency as saying it was looking into the circumstances of the sinking and was in touch with the authorities in Spain. Oboronlogistika and SK-Yug, a company LSEG lists as part of the group and the ship’s direct owner and operator, declined to comment on the sinking. Both entities were placed under sanctions by the United States in 2022 for their ties to Russia’s military as was the Ursa Major itself.
La Verdad said a breach on the starboard side of the Ursa Major matched the size and characteristics of damage caused by a supercavitating torpedo with a 500-millimetre warhead. Such torpedoes are used by Russia, China, and some NATO countries. Spanish investigators were particularly interested in two blue containers mounted on the stern of the ship that did not match the cargo description provided by the vessel’s captain, Igor Anisimov.
Investigators believe the containers held two VM-4SG reactors designed for nuclear submarines. According to the original plan, the reactors were to be shipped from St. Petersburg to the North Korean port of Arson, located just a few kilometres from Vladivostok — the vessel’s officially declared destination.
And, the transit of Russian ships through the Strait of Gibraltar has intensified in the last days of 2025 and the beginning of 2026, according to maritime observer Michael J. Sánchez, who has recorded the passage of several merchant ships and oil tankers, some of them subject to international sanctions, between 30 December and 1 January.
During that period, at least five Russian-flagged vessels crossed this strategic passage, two of which were included on the sanctions lists of the United States (OFAC) and the European Union and the United Kingdom (OFSI), once again placing the Strait at the centre of the debate on the control and surveillance of this key maritime corridor.