The emergency services said that there were 16 people on board the helicopter, among them 13 tourists, one a child, and three crew members. Eight people were said to have survived the crash.
"Eight people are alive, have been rescued," an emergencies service spokesman told Sputnik.
The rest are presumed to be missing and "are being looked for". The cause of the crash remains unknown.
According to preliminary information from the emergency service, a helicopter with tourists on board crashed in the area of the Kronotsky Nature Reserve.
"At 00:50 (Moscow time) on August 12, 2021, information was received about the crash landing of a Mi-8 helicopter of the Vityaz-Aero airline in the area of the Kuril Lake of the Kronotsky Nature Reserve", said the Russian Emergencies Ministry, noting that a helicopter with rescuers "is being readied".
A source from the emergency service told Sputnik that the aircraft fell into Kuril Lake. Huntsmen working on the territory of the Kronotsky Nature Reserve were said to have seen the helicopter fall.
The governor of Kamchatka, Vladimir Solodov, departed for the crash site, accompanied by medics and emergencies services staffers.
No further details were immediately available.