Preliminary reports identified the dead as the seven helicopter crew members, an employee of the airbase in Chita, the region where the crash occurred, a reporter and cameraman working for Rossia television channel and two reporters for the weekly Ejenedelni Journal.

The helicopter burst into flames when it crashed and there were no survivors, ITAR-TASS news agency quoted the ministry as saying.

A rescue team has been sent to the area, located in southeastern Russia, near the border with Mongolia. President Vladimir Putin is reported to have asked Emergencies Minister Sergei Shoigu to go to the scene.

The Russian media gave varying reports of the circumstances of the crash.

A Rossia reporter quoted the emergencies ministry, which owned the helicopter, as saying the accident occurred when the craft emptied the contents of its water tank onto the burning forest. The tank, suspended under the helicopter sprang back up when it was emptied, hitting a propellor and destabilising the craft.

But Ria-Novosti quoted sources close to the ministry as saying the helicopter had hit a high-voltage power cable.

Fires are currently raging through 36,000 hectares of forest in Chita and more than 2,000 firefighters have been sent to combat the blazes, ITAR-TASS quoted the local natural resources ministry as saying.

Brought into service in 1985, the Mi-26 is the world's most powerful helicopter and is used mainly by the Russian armed forces.

It can lift a 20-tonne load, has an eight-blade propellor measuring 32 metres (106 feet) in diametre and is considered extremely reliable.

SPACE.WIRE