At least four people have been killed and dozens are missing after an avalanche struck a team of mountaineers high in the Indian Himalayas, reports BBC.
The 34 trainees and seven instructors were practising navigation when they were hit on their descent from a peak in the northern state of Uttarakhand.
Eight of the party are believed to have been rescued and the rest are trapped in a crevasse, rescuers say.
Bad weather is hampering search efforts.
Local media reports say the number of casualties may rise significantly.
The group was made up of trainees from the nearby Nehru Institute of Mountaineering. It said they had been returning from Mount Draupadi Danda-2 (5,670m; 18,602 feet) when the avalanche struck.
Authorities were alerted at around 09:30 local time on Tuesday (04:00 GMT), rescue workers said.
"We have confirmation of four deaths out of the 33 people trapped. Around eight of them have already been rescued and the rest are trapped in a crevasse," Ridhim Aggarwal from the State Disaster Response Force told AFP news agency.
Rescue efforts will continue as long as the weather allows, he said.
Earlier, Uttarakhand police chief Ashok Kumar told Reuters news agency: "The Indian Air Force is doing an aerial recce of the mountain where this happened. It is not easy to reach the spot."
Defence Minister Rajnath Singh wrote on Twitter: "Deeply anguished by the loss of precious lives due to landslide which has struck the mountaineering expedition carried out by the Nehru Mountaineering Institute in Uttarkashi."
It comes a week after the body of famed US ski mountaineer Hilaree Nelson was found in the Nepali Himalayas.
Ms Nelson, regarded as one of the greatest mountaineers of her generation, was reported to have fallen into a deep crevasse after reaching the summit of Mount Manaslu.
On the same day she went missing, one person was killed and more than a dozen injured in an avalanche lower down on the same peak.