US military helicopters yesterday began reconnaissance trips to assess remote areas of Nepal devastated by an earthquake that killed more than 7,300 people, an official said.

Nine days after a 7.8-magnitude quake brought death and destruction to the Himalayan nation, the helicopters surveyed mountain villages.

Four tilt-rotor Ospreys have also arrived in Nepal.

"Only the 'Hueys' (helicopters) have gone out so far for reconnaissance flights to try to identify areas in need of relief. No Ospreys have been out," a US embassy official told AFP on Monday.

The Ospreys and a US Air Force C-17 aircraft touched down in the capital Kathmandu on Sunday.

"They'll have multiple aims. They'll be delivering relief supplies, they might do some rescues, they'll also do assessments,” US ambassador Peter W Bodde told reporters.

"They're going to make an immediate difference," said US Brigadier General Paul Kennedy.

A Nepalese official said the US aircraft would also airlift victims out of remote areas which suffered some of the worst devastation following the April 25 quake.

"They are also assisting any casualties in mostly

the eastern side of Nepal... places worst hit like Sindhupalchowk, Gorkha area," Surya Prasad Silwal, the home ministry secretary, told AFP.

He said later that some foreign rescue teams had been asked to leave "now that there is no chance of any survivors".

While the official death toll for Nepal rose to 7,365 on Monday, with some 14,000 injured, authorities warned the final tally would be much higher. More than 100 people were also killed in neighbouring India and China.

Finance Minister Ram Sharan Mahat had said the death toll was likely to jump once relief teams reached mountain villages flattened in the worst quake to hit the nation in more than 80 years.

Everest climbs 'almost impossible'

Meanwhile, officials in Nepal yesterday said climbing Mount Everest this season is "almost impossible" because the routes have been damaged by avalanches triggered by last month's earthquake.

They warn that it will take time for the routes to be remade. The government has not announced an official decision. The window for reaching the summit of Everest closes at the end of May because of the start of the monsoon, and some climbers are already waiting at Base Camp in the hope of the route re-opening soon.