Two big-name European mountain climbers and their Sherpa guides got into a big fight high up on Mount Everest, forcing the foreign mountaineers to return to base camp.

Nepal Police are investigating the claims by Switzerland's Ueli Steck, Simone Moro from Italy, and British photographer Jonathan Griffith. The group was attempting to climb a new "undisclosed" route to the top of Everest without using supplementary oxygen.  But, in between Camps Two and Three at 7,470 meters, the Europeans allegedly ignored orders to wait while the Sherpas were rigging ropes, and the leader of the Sherpas says he was hit by falling ice.

Both sides accuse the other of starting the violence.  After the argument Steck, Moro, and Griffith descended to cap Two where they claim they were confronted by a group of a hundred Sherpas, punching and kicking, and that they were saved only because another group of climbers intervened.

Straddling Nepal and China, Mount Everest is the world's highest mountain rising to an altitude of 8,848 meters.