ISLAMABAD - Hopes are fading for two European climbers, Tom Ballard and Daniele Nardi, who went missing on the world’s ninth-highest peak and ‘killer mountain’ Nanga Parbat. However, the rescuers are not willing to give up.

The search has not been called off, said Ali Muhammad Saltoro, of Alpine Adventure Guides Pakistan, the tour operator to the climbing expedition.

He said an aerial search was scheduled on Thursday but could not be materialised due to bad weather and security concerns.  Saltoro said Askari Aviation, has been paid in cash and guarantee to carry out the search operation.

Four rescuers Alex Txinko, Felix Criado, Ignacio De Zuloaga and Joseph Sanchis are present at the base camp and helicopter will be sent when they will signal, saltoro said.

Commenting on reports that rescuers have found two ‘Silhouettes’ on the passage taken by missing climbers, he said it was early to declare them their tents.

Every year many tents are installed on the mountain, the missing climbers were using tents with logo - salewa and ferrino, no logo has been identified so far, he said.

The British climber Tom Ballard, 30, and his Italian climbing partner Daniele Nardi, 42, were last heard at their base camps through a satellite phone, last Sunday from around 6,000 meters height on Nanga Parbat.

Missing climbers were attempting to climb the Himalayan giant in winter via a rock spur called Mummery Rib, a route, never been successfully completed, before.

The concern for Ballard, is doubly painful for those who have met his mother- who died during climbing in the same region. Twenty four years ago Ballard’s mother Alison Hargreaves - the first woman to conquer Mount Everest solo and without bottled oxygen - went missing on a nearby mountain K2. Her body was never found.

“I met Alison in Skardu, she was brave inspiring professional climber, coming straight from Everest summit, It was shocking to know she died in an avalanche while descending K-2,” said Afzal Shigri, a seasoned mountaineer.

He said in 1997, young Tom along with his other family members visited the K-2 area, and they told him his mother was resting in the mountain, maybe he came in search of his mother, he said.

In the 1980s Alison was one of the few British women who were recognised for their climbing efforts.

According to mountaineering blogger, Mark Horrell, Hargreaves, was in heavy debts, and her quest to climb the world’s three highest mountains – Everest, K2 and Kangchenjunga – in a single year, was for the family, young Tom and Kate Ballard.