The twin-engine Antonov An-28 was attempting to make an emergency landing when it went down in a wooded area, the Russia news agency RIA Novosti reported.
Kamchatka's special programs minister said the plane was on a flight from the regional capital Petropavlovsk-Kamchatsky to an airfield in the village of Palana when it lost contact with air traffic control.
The plane was carrying 12 passengers, two of them children, and a crew of two when it crashed.
Four survivors of the crash were taken to a local hospital in serious condition.
Investigators said they have not ruled out mechanical failure, weather or crew error as possible causes of the crash.