A mountaineer on Everest has tweeted a plea for helicopters to be sent to a partly buried base camp, after the earthquake in Nepal triggered an avalanche on the mountain.
Around 300 people who were staying at an Everest base camp are feared to have been caught in an avalanche.
So far 10 people have been confirmed dead on the mountain. Chinese media have reported a Chinese climber and two Sherpa guides are among the dead.
There are also numerous injuries and an unknown number of climbers missing.
Romanian mountaineer Alex Gavan tweeted that there has been a "huge disaster" on the peak, begging for rescue helicopters before more of the injured die.
"Helped searched and rescued victims through huge debris area. Many dead. Much more badly injured. More to die if not heli asap," he tweeted.
Earlier he described "running for life from my tent" as the avalanche descended.
An official from the Nepalese tourism department said that areas of the Everest base camp have been buried.
"We don't have the details yet, but 10 have been reported dead so far, including foreign climbers," Gyanendra Kumar Shrestha said.
Norwegian climber Carsten Lillelund Pedersen said that he and a Belgian companion were close to the Everest base camp at an altitude of 5,000m at the Khumbu Icefall – a notoriously dangerous area – when the earthquake hit.
"We are starting to receive the injured, the most severe of them with many fractures, he was blown away by the avalanche and broke both legs. For the camps closer to where the avalanche hit, our Sherpas believe that a lot of people may have been buried in their tents," he wrote on Facebook.
Ang Tshering of the Nepal Mountaineering Association confirms that the worst avalanche apparently happened between the Khumbu Icefall and the base camp.
Around 300 climbers are believed to be at base camp.
Silence from base camp
"We are trying to reach them to see if they are safe, but the phones are not working," said deputy superintendent Chandra Dev Rai of the Nepalese police.
Captain Tim Bradshaw is leading a British Army climbing team on Everest. Bradshaw is on the Tibetan side of the mountain, away from the epicentre of the quake, and says that there are no casualties in his group. Even so, he reported a serious rockfall.
He told Sky News that hit his tent started to "rock and move" as the earthquake took hold.
"Almost like thunder huge boulders started to break around us from the side of the mountain and roll down towards the bottom, towards base camp," he said.