Search and rescue services are trying to recover wreckage from a Russian Tupolev Tu-142 maritime reconnaissance aircraft which crashed in the Tatar Strait off the country's far eastern coast.
Radar contact with the four-engined aircraft was lost at 21:17 yesterday.
The Russian defence ministry says it had 11 crew members on board and was carrying out a training flight.
It says that a "round-the-clock search" is taking place in a defined zone for the crew and sections of the aircraft.
Naval and civilian vessels, as well as aircraft and helicopters, are participating, and the hunt has enlisted assistance from deep-sea rescue ships.
Some fragments of the Tu-142MZ have been located but the ministry has not indicated any evidence of survivors.
The strait separates the Russian mainland from Sakhalin Island.
No further information has been disclosed regarding the circumstances of the accident, but the ministry says it is "considering all possibilities, including technical".
Source: Flight International
