"Last night, a fire occurred on board the Daniil Moskovsky nuclear-powered submarine in the Barents Sea," the ministry's spokesman said. "Two crewmembers were killed in the fire, but there is no danger of an explosion."
He said a fire in the electrical circuit caused an automatic shutdown of the nuclear reactor, but that it was quickly extinguished.
The K-414 Daniil Moskovsky, a Victor III class nuclear-powered submarine, was commissioned by the Russian Navy in March 1991 and participated in a search-and-rescue effort during the Kursk nuclear submarine tragedy in August 2000.
The surfaced submarine is being towed to a naval base, the spokesman said.
The Northern Fleet's military prosecutors have launched a criminal investigation into the incident.