A Russian nuclear submarine that caught fire in a shipyard was submerged to extinguish the blaze yesterday. The emergency move came after premature reports that the flames had been put out. Defence sources said the submarine's weapons and critical elements of its nuclear reactor had been removed before the fire broke out. Scroll down for video . Smoke: The submarine that caught fire in a shipyard was submerged to extinguish the blaze yesterday . Defence sources said the submarine's weapons and critical elements of its nuclear reactor had been removed before the fire broke out . The 500ft-long Oryol was in dock at Zvezdochka shipyard in Severodvinsk, 620 miles north of Moscow, on the White Sea. The submarine's dry dock was filled with water to put out the fire - a move taken after news agencies carried reports saying the emergency was already over. 'Preparation for filling the dry dock with water is underway,' said spokesman Ilya Zhitomirsky. 'The operation is necessary to extinguish the fire completely.' Filling the hull with foam to stop the flames spreading was 'not yielding results,' said a source. 'No workers or members of the crew were harmed during the fire,' said Zhitomirsky. A source told TASS news agency the submarine's nuclear reactor had been shut down prior to the blaze. 'The active zone of the reactor was unloaded at the start of repairs a few years ago,' the source said. Emergency: A submarine undergoes repairs at Zvezdochka shipyard in Severodvinsk in 2012. A nuclear submarine has caught fire at the naval base after welding set insulating material alight during repairs . The 'Yekaterinburg' nuclear-powered submarine at her mooring at the Zvezdochka shipyard (file picture) Remote location: The submarine was being repaired in a shipyard in Severodvinsk, around 1,000 kilometers (620 miles) north of Moscow on the White Sea . The news agency reports said the fire had started during welding, causing insulation materials to catch fire. A similar blaze in 2011 nearly led to a nuclear disaster when a blaze engulfed a nuclear-powered submarine carrying atomic weapons. A leading Russian magazine reported the threat months after the blaze, contradicting official assurances that it was not armed. The Oscar II-class submarine is capable of carrying nuclear-tipped cruise and anti-submarine missiles.
Officials insist there were no weapons on board and atomic reactor is safe . Fire had started during welding, causing insulation materials to catch fire . The Russian nuclear submarine was submerged to extinguish the fire .