Rescuers have given up searching for three Sherpa guides missing two days after the deadliest-ever accident on Nepal's Mount Everest killed at least 13 people and shocked the mountaineering world.

Snow and huge chunks of ice swept down the perilous, crevasse-riddled Khumbu Icefall on Friday as guides ferried supplies to upper camps for foreign climbers trying to reach the summit of the world's tallest mountain.

Helicopter searches and teams scouring the area on the ground Friday and Saturday found no sign of the missing men, who rescuers believe were knocked into crevasses or trapped under snow while preparing the route for climbers.

Rescuers brought six bodies from the base camp to Katmandu over the weekend and have kept them at a Sherpa Buddhist monastery in accordance with tradition. The rest were handed over to families in the Solukhumbu region, where the accident took place.

Shocked and demoralized by the accident, several Sherpa guides have called for the 8,848-meter (29,029-foot) mountain to be closed to expeditions during the popular climbing season, which will run through May this year, as a mark of respect for the dead.