An avalanche buried over 100 Pakistani soldiers near the Siachen glacier on the border with India on Saturday, the Army said, adding that casualties were expected.
Several Pakistani television channels reported earlier that about 150 soldiers were trapped.
Some reports suggested that 135 soldiers, including a colonel, had been hit by the avalanche.
“At six o’clock this morning this avalanche hit a (military) headquarters. Over 100 soldiers and personnel are trapped,” Army spokesman Major-General Athar Abbas said.
Abbas further said a rescue operation was underway.
In a statement, Prime Minister Yousuf Raza Gilani expressed his shock at the incident, which he said “would in no way undermine the high morale of soldiers and officers”.
A helicopter rescue team was searching for the soldiers with sniffer dogs, he added.
The incident occurred at a spot near Skardu in the eastern Karakoram mountain range.
Gyari is home to an important battalion headquarters and at one time, up to 3,000 soldiers were based in the area. Following the ceasefire along the frontiers in Jammu and Kashmir, both India and Pakistan reduced troop levels.
Indian and Pakistani forces, estimated to number between 10,000 and 20,000 troops combined, have faced off against each other in mountains above the Siachen glacier in the Karakoram range since 1984.
The no-man’s-land of Siachen is 20,000 feet above sea level. Military experts say the inhospitable climate and avalanche-prone terrain have claimed more lives than gunfire.