MADRID — A Russian ship that sank in the Mediterranean after its engine room exploded may have been carrying pieces for nuclear reactors used in submarines, a Spanish government document shows.

The Ursa Major sank on Dec. 23, 2024, between Spain and Algeria while allegedly on a journey from St. Petersburg to Russia’s eastern port of Vladivostok. Two crew members were lost while 14 other people were saved by Spanish rescue craft.

It has emerged that the Ursa Major’s Russian captain told Spanish port authorities following his rescue that the vessel was carrying parts for nuclear reactors suitable for use in submarines.

In a written response to opposition lawmakers, the Spanish government wrote that the ship’s captain “confessed” that the ship was carrying “components for two nuclear reactors similar to those used in submarines.”

The response was included in a document registered by the Spanish parliament on Feb. 23 and reported by CNN on Tuesday. The document has been seen by The Associated Press.

At the time of the sinking, the Russian state-owned ship owner, Oboronlogistika, said that the Ursa Major was sabotaged. It said three powerful explosions damaged the boat just above the water line in what the company described as a “terrorist attack.”

Oboronlogistika was established under Russia’s defense ministry and placed under U.S. and European Union sanctions for its ties to Russia’s military.