The Antonov-12 plane carrying nine crew members and two passengers as well as 16 tons of food was en route on August 9 from the Far East city of Magadan northwards to the Chukotka peninsula when it disappeared from radars some 300 km (190 miles), from its take-off point, the Russian Far East Transport Prosecutor's Office said on its website.

The pilots reported a fuel leak and an engine fire to air traffic controllers but didn't manage to return to the departure airport for an emergency landing and lost communication, the office said.

State-run RIA-Novosti newswire cited witnesses who said they had seen the plane falling to the ground near the village of Omsukchan in the Magadan region.

The Emergency Situations Ministry told Russian state TV that dozens of rescue workers were dispatched to the accident area but the search operation is hindered by thick fog and nighttime. The ministry wouldn't report the fatalities until the bodies are officially discovered.

But Russia's Investigative Committee confirmed the fact of the crash in a press statement, and said it opened a criminal probe on charges of violation of air safety rules but nobody has been brought responsible for the crash yet. A group of experienced investigators and forensic experts were sent from Moscow, the committee said.

Antonov-12 cargo planes have been in operation since the late 1950s. The plane is capable of carrying up to 20 tons of cargo, 90 passengers and can fly at ranges over 5,000 km (3,125 miles).