The incident on the Moskva missile cruiser occurred after ammunition on board blew up, Interfax news agency quoted the Russian defense ministry as saying, according to Reuters.
"As the result of a fire on the Moskva missile cruiser, ammunition detonated," it said in a statement.
Maksym Marchenko, governor of the region around the Black Sea port of Odesa, said in an online post that the 12,500-tonne ship was hit by two missiles, without providing evidence.
"Neptune missiles guarding the Black Sea caused very serious damage," he said in an online post.
MP/PR