Pakistani soldiers dug into a massive avalanche in a mountain battleground close to the Indian border on Saturday, searching for at least 135 people buried when the wall of snow engulfed a military complex.

More than 12 hours after the disaster at the entrance to the Siachen Glacier, no survivors had been found. Al Jazeera is reporting that 12 bodies have been found as of late Saturday but there has been no other confirmation.

"We are waiting for news and keeping our fingers crossed," said army spokesman Maj. Gen. Athar Abbas. "It's on a massive scale. Everything is completely covered."

The military said in a statement that at least 124 soldiers and 11 civilian contractors were missing.

Hundreds of troops, sniffer dogs and mechanical equipment were at the scene, but were struggling to make much headway into the avalanche, which crashed down onto the rear headquarters building in the Gayari sector —more than 4,000 metres above sea level — early in the morning, burying it under some 24 metres of snow, said Abbas.

Siachen is on the northern tip of the divided Kashmir region claimed by both India and Pakistan.

World's highest battlefield

Both countries station thousands of troops there, who brave viciously cold temperatures, altitude sickness and high winds for months at a time. Troops have been deployed at elevations of up to 6,700 metres and have skirmished intermittently since 1984, though the area has been quiet since a ceasefire in 2003. The glacier is known as the world's highest battlefield.

In a statement, 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 headquarters in Gayari is the main gateway through which troops and supplies pass on their way to other more remote outposts in the sector. It is situated in a valley between two high mountains, close to a military hospital, according to an officer who was stationed there in 2003.

"I can't comprehend how an avalanche can reach that place," said the officer, who didn't give his name because he is not authorized to speak to the media. "It was supposed to be safe."

More soldiers have died from the harsh weather than combat on the glacier, which was uninhabited before troops moved there.

Conflict there began in 1984 when India occupied the heights of the 78-kilometre-long glacier, fearing Pakistan wanted to claim the territory. Pakistan also deployed its troops. Both armies remain entrenched despite the ceasefire, costing the poverty-stricken countries many millions of dollars each year.

Pakistan and India have fought three wars since the partition of the subcontinent on independence from Britain in 1947. Two of the wars have been over Kashmir, which both claim in its entirety.