A photo from the Portuguese Air Force shows the “Ursa Major” as the Russian ship sailed through Portuguese waters in December 2024. image: Portuguese Air Force
A Russian cargo ship sank off the coast of Spain in December 2024 under unclear circumstances. A CNN investigation suggests it was carrying two nuclear submarine reactors, possibly as supplies for North Korea.
May 12, 2026, 7:52 p.mMay 12, 2026, 7:52 p.m
Loud CNNwhich has been investigating the case for months, the “Ursa Major” exploded around 100 kilometers off the Spanish Mediterranean coast on December 23, 2024 and then sank. Two crew members were killed. The circumstances of the sinking have not yet been fully clarified.
Russian captain Igor Anisimov told Spanish investigators that the ship was carrying “components of two nuclear reactors, similar to those in submarines.” He stated that he was not sure whether they were loaded with nuclear fuel. According to the CNN report, he also believed that the ship was originally supposed to call at the North Korean port of Rason.
Official manifesto and reality
The public cargo manifest of the “Ursa Major” only listed two large “manhole covers”, 129 empty shipping containers and two Liebherr cranes as cargo. The ship was officially on its way from St. Petersburg to Vladivostok – both ports are in Russia and there is an extensive rail network between them. The Spanish investigators found this route implausible.
Two Russian military ships accompanied the “Ursa Major” through Portuguese waters, but withdrew shortly before the Spanish maritime area. After the ship got into distress and the Spanish sea rescue team arrived, the Russian escort ship “Ivan Gren” asked those around them to keep a distance of two nautical miles and demanded the immediate return of the rescued crew. Shortly afterwards, four more explosions were registered – and the “Ursa Major” sank.
US nuclear bomber sniffer planes over the wreckage
The mysteries surrounding the sinking deepened in the months that followed. The Russian ship “Yantar,” classified as a spy ship by NATO, spent a week above the wreckage. Four further explosions were recorded, which were possibly aimed at remnants of the cargo on the seabed.
The US military also flew a so-called “nuke sniffer” over the accident site twice – a rare special aircraft of the WC-135 type that is used to detect nuclear activity. A spokesman for the responsible US base in Nebraska confirmed the basic function of the aircraft to CNN, but did not provide any information about specific findings.
No access to the wreck, no answers
The wreck lies at a depth of around 2,500 meters off the Spanish coast. The Spanish government stated that recovery of the data recorder would not be possible without significant technical resources. Experts have questioned this assessment. It is unclear what findings the investigators actually have and what they are withholding.
The Spanish government only publicly commented on the incident after pressure from parliamentarians – and then only briefly. Several Western security and intelligence officials told CNN the case was “strange” but offered no alternative explanation for the explosions and the unusual Russian response to the ship’s sinking. (mke)