An avalanche on the high-altitude Siachen glacier that is disputed between India and Pakistan killed at least six Indian soldiers on Sunday when their outpost was swept away before dawn.

Thousands of soldiers from both nations endure bitter conditions on the glacier, which is dubbed "The world's highest battleground", due to the long-running territorial dispute.

An estimated 8,000 troops have died since 1984, almost all of them from avalanches, landslides, frostbite, altitude sickness or heart failure rather than combat.

"The avalanche struck a forward post early on Sunday morning, burying seven soldiers," army spokesman Lieutenant Colonel J.S. Brar told AFP.

"Rescue operations were launched immediately and so far six bodies have been recovered. The rescue effort is still ongoing."

In April 140 Pakistani soldiers were killed by a huge avalanche on Siachen.

Kashmir has been the cause of two wars between India and Pakistan and the nuclear-armed rivals fought over Siachen in 1987, though guns on the glacier have largely fallen silent since a peace process began in 2004.