NEW DELHI — Eight mountain climbers missing for more than a week in the Indian Himalayas appear to have died in an avalanche, disaster response officials said Monday, citing aerial photographs that show bodies in the snow.

The climbers — four Britons, two Australians, one American and one Indian — had been out of contact since May 26, when they set off “with the ambition of summiting a virgin peak” on Nanda Devi, India’s second-highest mountain at more than 25,000 feet.

Amit Chowdhury, an official at the Indian Mountaineering Federation who is helping to coordinate search efforts with Indian forces, said operations had been hindered by bad weather. A close study of photographs taken during a helicopter flight early Monday showed at least five bodies, he said.

“It now appears that all the climbers were caught in an avalanche quite close to the spot where they had camped for the night,” Mr. Chowdhury said. “Plans are now being made to retrieve the bodies.”