Pakistan has formally protested against India's decision to allow tourists to visit the disputed Siachen glacier.
More soldiers die of cold than bullets on the Siachen glacier
Siachen is on the border of Pakistan- and Indian-controlled Kashmir, a region that the two sides have fought and argued over for decades.
India said last week it would take trekkers to the mountain region.
Pakistani spokeswoman Tasnim Aslam said: "We summoned the Indian deputy high commissioner and conveyed our strongest reservations.
"We told him that tourism should not be allowed in disputed territories.
"Siachen is a disputed area and such initiatives will harm the dialogue process between the two countries," Ms Aslam said.
Pakistan and India have been locked in a bitter dispute over the Siachen glacier since 1984.
Both countries have deployed thousands of troops on what is described as the highest battlefield in the world, at around 5,500m (18,000ft).
There have been various attempts to reach a compromise through talks.
They have led to some improvement in transport and diplomatic links, but as yet there has been no substantial progress on their main disagreement - the divided Kashmir valley.
After talks in 1989, Pakistan says both countries agreed to pull back troops to their pre-1984 position.
It accused India of not honouring this agreement - a position India denies.
Fighting has continued and the neighbours continue to deploy thousands of troops at a cost of hundreds of millions of dollars a year.
But more soldiers, on both sides, have died from the -40C (-40F) temperatures than from enemy fire.
The chief of staff of India's army, Gen JJ Singh, said last week: "Since Siachen is a part of India, I have decided to allow adventure tourism so that people enjoy the natural beauty there and also tell the whole world."
Pakistan maintains this move could lead to higher tensions in Siachen.
"Siachen is a battlefield," Ms Aslam said. "Allowing tourists into the area could have severe consequences."