A devastating avalanche that engulfed a Pakistan army base in the Himalayas has left 135 feared dead, the Pakistan army says.
A security official told Sky sources more than 15 bodies have been recovered from the Gayari sector of Siachen in the country's north.
More than 12 hours after the disaster at the entrance to the Siachen Glacier in the Karakoram mountain range, no survivors had been found.
Troops with sniffer dogs, aided by helicopters, have been trying to find signs of survivors in the snow.
But snow left by the avalanche was up to 80 feet (25 metres) deep over an area a kilometre wide, state television quoted army spokesman Major General Athar Abbas as saying.
A team of doctors and paramedics has also been sent to the mountainous area, a security official said.
Pakistan High Commissioner Wajid Shamsul Hasan told Sky News that a huge rescue operation is underway.
"It is a very horrendous tragedy," he said.
"Attempts are being made to rescue as many [soldiers] as possible. The terrain is most difficult... it is the highest battlefield in the world."
State-run Pakistan television said rescuers were facing difficulties getting heavy machinery to the far-flung area.
Army spokesman Major General Athar Abbas said: "At six o'clock this morning this avalanche hit... over 100 soldiers and personnel are trapped.
"We are waiting for news and keeping our fingers crossed."
In a statement, Pakistan prime minister Yousuf Raza Gilani expressed his shock at the incident, which he said "would in no way would undermine the high morale of soldiers and officers."
The Kashmir region - of which Siachen is a part - is divided between fierce rivals Pakistan and India, and is claimed by both in full.
Thousands of Pakistani and Indian troops are based on the Siachen Glacier, which is 20,000 feet (6,000 metres) above sea level.
More soldiers have died from natural disasters than actual fighting in the region.
Avalanches and landslides frequently block roads and leave communities isolated in the mountains of Pakistan, neighbouring Afghanistan and Kashmir.
In February, at least 16 Indian soldiers on duty in the mountains of Kashmir were killed when two avalanches swept through army camps.
Most of the time on Siachen, the bad weather prevents any troop movement and despite the heavy deployment, clashes are generally low-level skirmishes involving a few dozen troops.