Firefighters have put out a blaze on the exterior of a Russian nuclear submarine that broke out during repairs in the northern Murmansk region, a minister said Friday.

"The fire has been liquidated. There is no burning," Emergency Situations Minister Sergei Shoigu told a meeting of officials, adding radiation monitoring would now go back to normal after being stepped up following the fire.

"We are halting the increased monitoring of radiation and will move on to normal regime," he said in comments published by Russian news agencies. Shoigu said his ministry would now hand over recovery work to the ministry of defense.

The fire on the rubberised coating of the Delta IV class Yekaterinburg submarine was the latest serious accident to have struck Russia's navy in the last years.

There had been a succession of contradictory reports after the fire broke out on Thursday afternoon, with several officials earlier quoted as saying the fire had been put out while firefighting was still continuing.

But Shoigu insisted that Russia was telling the full truth about the accident.

"Disinformation needs to be stopped. We have no secrets and there never were any. We need to give reliable information and we put it all online," he said.

"We need to stop any insinuations. There is no need to spoil people's moods before the New Year holidays."