Hundreds of military personnel were deployed in the Indian Himalayas on Monday to help find at least 125 people unaccounted for after a part of a glacier broke away, setting off a torrent of water, rock and dust down a mountain valley.

Sunday's violent surge swept away a small hydro electric project called Rishiganga and damaged a bigger one further downstream.

Most of the missing were people working on the two projects, one of the many the government has been building deep in the mountains of Uttarakhand state as part of a development push.