Overview
- Spanish investigators, cited by La Verdad and subsequent reports, assessed that the Ursa Major carried two undeclared VM-4SG nuclear submarine reactor casings concealed under blue tarps.
- The vessel’s circuitous route from St. Petersburg through the Mediterranean toward Vladivostok suggested a likely transfer to North Korea’s port of Rason, with heavy cranes aboard to handle the load at limited facilities.
- The ship sank on December 23, 2024, after explosions, with 14 crew rescued and two engineers missing, and there is no confirmed evidence that nuclear fuel or other radioactive material was aboard.
- Investigators documented a roughly 50-by-50-centimeter breach with metal bent inward, while Spain’s seismic network recorded underwater shockwaves equivalent to 20–50 kilograms of TNT near the time of the sinking.
- The operator Oboronlogistika labeled the event a terrorist attack, Russian naval units asserted control near the site and later deployed the deep-sea vessel Yantar, and formal international confirmation of the cargo and any perpetrator remains outstanding.