The death toll in the worst-ever mountaineering accident on Mount Everest today rose to 13 as rescuers dug out a body buried under piles of snow, a day after a massive avalanche struck the world's highest peak killing 12 Nepalese Sherpa guides.

Rescue work started this morning with Nepal Army, Armed Police Force personnel and climbers digging through piles of snow and ice for four Sherpa guides buried on the Everest when they recovered a dead body.

This takes the death toll in yesterday's accident to 13 even as three sherpas remain missing.

Authorities have ruled out hope of finding any more survivors from the avalanche that swept away the climbers as they were making their way up to the higher camps to fix ropes and dig a path for foreign climbers ahead of next month's peak season.

The avalanche occurred at around 6:45 am at an altitude of about 5,800 metres in an area known as the "popcorn field" which lies on the route to the treacherous Khumbu icefall.

The dead bodies of 12 climbers were recovered from the accident site yesterday while four had remained missing. Ten others were injured, including three seriously.Seven of the 12 bodies have been handed over to their families in the Everest region, while the other five were taken to Kathmandu.

Nepal government has announced a compensation of Nepali Rupees 40,000 to the relatives of the deceased.

Earlier last month, Nepal government had announced several steps to improve safety of climbers in view of the heavy flow of climbers and speed up rescue works.

The steps included the deployment of officials and security personnel to the base camp at 5,300 metres, where they will stay throughout the spring to assist and monitor climbing.

Around 4,000 people have scaled Mt Everest since 1953 when Tenzing Sherpa and Edmund Hillary made it to the summit of the peak.

Over 250 people have died while attempting to climb the Everest. This year, over 300 climbers have taken permission to climb the Everest.

The accident comes during the peak climbing months of April and May as hundreds of climbers converged at base camp in the hope of scaling the 8,848-metre-high summit. Ethnic Sherpas act as guides for the mostly-foreign clients.

The worst recorded accident on Everest has been a snowstorm on May 11, 1996, that killed eight climbers. Six Nepalese guides were killed in an avalanche in 1970.