The fire at the Yekaterinburg nuclear submarine occurred while it was in dock for repairs at the Roslyakovo shipyard in the Murmansk region, said Irina Gretskaya, a spokeswoman for the Emergencies Ministry's branch in the area.
Gretskaya said the fire engulfed wooden scaffolding at the yard. "No one has been hurt and there has been no radiation leak," she said.
The Yekaterinburg is a Delta-IV-class nuclear-powered submarine that normally carries 16 nuclear-tipped intercontinental ballistic missiles.
Defense Ministry spokesman Igor Konashenkov told The Associated Press that all weapons had been unloaded from the sub and its reactor had been shutdown to safety before the repairs.
Konashenkov said the fire had started on the scaffolding and then engulfed the submarine's outer hull. He insisted that there is no danger of it spreading inside.