ISLAMABAD (Web Desk) – Stepping up the search operation for two missing American mountain climbers, Pakistan deployed army helicopters to find the pair who went missing six days ago while trying to summit a mountain.

Kyle Dempster and Scott Adamson began their ascent of the 7,285-metre (23,900-foot) Ogre-II peak off the Choktoi Glacier in the Gilgit-Baltistan region of Pakistan on Sunday August 21, but went missing the next day.

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“Two helicopters belonging to military aviation flew over the mountains Saturday morning but there was no sign of the climbers, the search goes on” Karrar Haidri, a spokesman for the Alpine Club of Pakistan said.

The helicopter search has been delayed for days because of the adverse weather conditions.

Authorities vowed that a team of local high-altitude rescuers had been searching for the missing mountaineers for almost a week but bad weather has prevented them from ascending the peak.