Eight Californian firefighters and one of their helicopter pilots were presumed dead last night after their emergency aircraft crashed on Tuesday evening in a forest two hundred miles from Sacramento.

The firefighters had been trying to contain part of a blaze that had taken hold of more than 27 square miles of the Shasta-Trinity National forest in California. Much of the fire had already been contained.

Four of the thirteen firefighters and helicopter crew on board were flown to local hospitals with severe burns. The rest were missing, presumed dead. It is believed that the aircraft crashed at around 7.45pm on Tuesday night.

The cause of the crash is still uncertain, said Bob Madden, spokesman for Carson Helicopter Services of Grants Pass, Oregon, owner of the aircraft.

"We've heard both (that) they were taking off to take people back to base camp, or they were dropping someone off."

The helicopter caught on fire after hitting the ground, he added.

"Apparently the aircraft came down and impacted the terrain and then rolled down the mountain and it was after continuing a roll down the mountain and the aircraft took fire," he added.

A spokesman for the US Forest Service said that two factors - the remote location of the crash and the fact that the wreckage was still burning, had hampered further recovery attempts. Of the known survivors, Rick Schoeder, 42, was admitted to the Mercy Medical Center in Redding.

A spokesman for the hospital told The Times last night that Mr Schoeder remained in a serious condition, but that no other victims of the crash had since been treated at the centre.

Michael Brown, 20, Jonathan Frohreich, 18, both firefighters, and one unnamed co-pilot were also flown from the site of the crash to the University of California, Davis Medical Center in Sacramento. The centre failed to return calls last night. However, it is believed that Mr Brown's condition had improved yesterday to be described as "fair" while Mr Frohreich and the co-pilot remained in serious condition.

Arnold Schwarzenegger, governor of California, last night led messages of support to the victims: "We are praying for the swift recovery of all the victims, and our hearts go out to their loved ones."

Some of the firefighters, including those in the hospital, were employed by a firefighter contractor Grayback Forestry, based in Merlin, Oregon. Mike Wheelock, Grayback's founder and owner, would not confirm any deaths.

According to the US Forest Service, the helicopter had taken off from a remote area of the Shasta-Trinity National Forest. It added that a umber of firefighters who had been waiting to be collected by other helicopters tried to help to rescue their colleagues. However, about three dozen of them had been forced to spend the night in the open because it had become too dark for new helicopters to land. While the Federal Aviation Administration and the National Transportation Safety Board are conducting inquiries into the crash, the cause of the incident is still not known.

The 30-year-old helicopter, a Sikorsky S-61, was originally made in Connecticut and upgraded three years ago, Madden said, adding that it's not military surplus and has been used in firefighting for 10 years.

"We have 12 aircraft under contract to the US Fire Service," he said. "We're probably the largest operator of fire-fighting helicopters - we fight fires here, Canada, Mexico and Australia."

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