The Mi-8 helicopter carrying 17 passengers and crew including top regional officials and businessmen, crashed into the Munozero lake in the far northern Murmansk region on Saturday. Two survived the crash.
"There were 17 people on board. The bodies of 12 dead have been raised to the surface, the fate of three people remains unknown," the head of the emergency ministry's national crisis management centre, Viktor Yatsutsenko, was quoted as saying by the ITAR-TASS news agency.
The two survivors were in a "satisfactory condition" in hospital after being found floating in the lake still strapped to their chairs, Yatsutsenko said.
Ten out of the 12 dead have been identified, including the deputy governor of the Murmansk region, Sergei Skomorokhov, the RIA Novosti news agency reported, citing a law enforcement source.
The search for the missing was hampered by poor weather conditions with high winds and waves, rescuers told RIA Novosti.
The number of people on board was initially reported as 18, but fell to 17 as it emerged that one crew member did not board the helicopter.
"According to updated data, one of the crew members, a technician... did not fly," a source from law enforcement told ITAR-TASS.
Investigators said that possible causes of the crash were aircraft malfunction and bad weather conditions.
"The pilot found himself in difficult meteorological conditions, lost his sense of direction and hit the surface of the water," the Investigative Committee said in a statement.
PhosAgro, one of the world's top producers of phosphate fertilizers, said that the trip was organized by one of its subsidiaries to help regional authorities to develop the region's tourism potential and attract investors.