An avalanche on Mount Everest has left at least 12 Nepalese climbers dead and four missing.

Three survivors were being treated in Katmandu on Friday for severe injuries sustained in the fall. Officials claim the climbing accident is one of the deadliest in the Mountain’s history.

A relative of one of the injured guides said: “The group had woken up early on Friday and headed to higher camps to fix ropes, but were delayed by an hour because of the bad trail near an icefall area. Suddenly when they reached the site called ‘Popcorn (Field)’ the avalanche fell and buried many of them.”

A rescue mission to find the four missing men was ended early on Friday because of bad weather.

The month of May is seen as the best time to climb Everest, but the pay and conditions of local guides has become increasingly controversial as mounting numbers of Western climbers attempt to scale the world’s highest peak.