A helicopter carrying elite paramilitary mountaineers took off Wednesday for a “very high-risk” operation to retrieve five dead climbers and three others believed killed scaling a treacherous Himalayan peak.

Indian Air Force choppers spotted five bodies Monday on the slopes of Nanda Devi in Uttarakhand while looking for the four Britons, two Americans, one Indian and one Australian believed killed by an avalanche last week.

The remains of the three others, all part of originally a 12-member team led by highly experienced British climber Martin Moran, were believed to be nearby. Four other Britons split from the bigger group and were rescued on the weekend.

The mission to remove the bodies of five missing climbers, however, was halted after encountering technical problems, Reuters quoted officials as saying.

The recovery mission began at 5:00 am on Wednesday but soon encountered technical problems.

Four Indo-Tibetan Border Police (ITBP) trekkers and five Air Force personnel arrived at Nanda Devi Base Camp after they took off from Munsyari early today in an ALH (Advanced Light Helicopter) to join the search operation of the missing climbers.

The ITBP climbers were dropped by the helicopter 18,000-20,000 feet up India’s second-highest mountain.

An ITBP official confirmed that there will be no more sorties today to retrieve the bodies of eight missing climbers. The technical snag developed after three sorties were attempted.

Vijay Kumar Jogdande, District Magistrate Pithoragarh said, after three attempts, the helicopter came back to Pithoragarh adding that altitude, geography, and air turbulence at the location did not let the officials operate. “We will start operation with a different plan,” he said.

“A team will be dropped by a helicopter at a higher location where these problems do not arise. The team will be given a time of 3-4 days to get acclimatized to the weather and altitude. Then they will start the search operation keeping in mind their safety,” Jogdande added.

The team led by Moran had permission to climb the eastern peak of Nanda Devi but a Facebook post by Moran’s mountaineering firm on May 22 said that they planned to attempt “an unclimbed peak” around 6,500 metres (21,300 feet) high.

“This mountain range is more difficult to scale than Mount Everest. They knowingly risked their lives after changing their plans without informing the authorities,” an official involved in the operation told AFP on condition of anonymity on Tuesday.

“The permission was granted for Nanda Devi East, and any diversion is illegal. We were completely unaware of their changed plan and that turned fatal,” he said.

Officials said the 12 climbers had set out from Munsyari but separated into two groups a week later.

The groups communicated last on May 26, a day before heavy snow fell and massive avalanches hit the heights.

A military source said the climbers may have fallen from an ice ridge or an overhanging mass of snow during the avalanches.

(With agency inputs)