An Indian Air Force helicopter with two pilots crashed on Wednesday in Siachen Glacier close to the Actual Ground Position Line between India and Pakistan.
The pilots, identified as Squadron Leader S Basu and Flight Lieutenant A Sharma, are missing.
The Cheetah helicopter had got airborne from Siachen Base Camp at 0628 hours and lost radio contact at around 0700 hours while flying over northern glacier at an altitude of 16,000-18,000 feet, officials said in New Delhi.
It was on a routine flying mission when the mishap occurred, they said, adding that the cause of the crash was not known yet.
A search operation by the army and the IAF has been launched to trace the missing pilots and wreckage, but heavy snowfall is hampering the efforts, officials said.
A Court of Inquiry has been ordered into the mishap.