The two climbers, Alberto Zerain, a Spanish alpinist, and Mariano Galvan, an Argentinian national, went missing while attempting to summit the 8,125-metre peak.
“Helicopters have been trying to fly over the mountain since Wednesday but bad weather and poor visibility mean they haven’t found anything,” a police official at base camp told AFP.
“The mountain has been shrouded in cloud for the past few days and the rain is causing constant avalanches,” he said, speaking on condition of anonymity as he was not authorised to speak to the media.
Karrar Haidri, spokesman of the Alpine Club of Pakistan confirmed that the climbers had not yet been found.
“Bad weather is hampering rescue efforts however the attempts will continue,” he said.
A total of 14 foreign climbers were attempting to summit Nanga Parbat this year when bad weather forced them to return to base camp last week.
The two missing climbers left base camp on June 19 but were holed up in their tent for three days at an altitude of 6,100 metres (20,000 feet) due to bad weather. They tried to summit again but lost contact with fellow climbers last Friday.
The “Killer Mountain” Nanga Parbat earned its grisly nickname after more than 30 climbers died trying to conquer it before the first successful summit in 1953.
In 2013, gunmen shot dead 10 foreign climbers and their Pakistani guide at the Nanga Parbat base camp.
Northern Pakistan is a magnet for mountaineers and is home to some of the tallest mountains in the world, including K2 – at 8,611 metres, the world’s second highest peak, but often deemed a more challenging climb than the highest, Mount Everest.
Nestled between the western end of the Himalayas, the Hindu Kush mountains and the Karakoram range, the Gilgit-Baltistan region houses 18 of the world’s 50 highest peaks.
It is also home to three of the world’s seven longest glaciers outside the polar regions. Hundreds of its mountains have never been climbed.