The mortal remains of four military personnel were recovered from the five who were aboard an ALH WSI Army helicopter that crashed on Friday in the Upper Siang district of Arunachal Pradesh, according to the PRO (Defence) Tezpur.

The search operation for the one remaining personnel is underway.

The helicopter had taken off from Lekabali and crashed at 10:43 am around Migging (South of Tutting) in Arunachal Pradesh.

"A joint Search and Rescue Operation of Army and IAF was launched immediately which included 1 MI17, 2 ALH and 3 columns of Army," the PRO said.

The cause of the crash has yet not been known.

"A total of 5 Personnel were on board, during the Search and Rescue Operation, the team has recovered the mortal remains of four individuals out of the five till now. The cause of the crash at this stage is not known. Details are being ascertained," the PRO added.

Earlier today, Jummar Basar, Superintendent of Police Upper Siang, told ANI over the phone, "The site of the accident is not connected through road. A rescue team has been rushed."

Earlier on October 5 this year, an Indian Army pilot died in a Cheetah helicopter crash near the Tawang area of Arunachal Pradesh.

(With inputs from ANI)