The helicopter crash took place 25 kilometres west of Nahanni Butte in southwestern Northwest Territories. (CBC)

Two helicopter passengers were killed Tuesday when the aircraft crashed in the Liard Mountains in southwestern Northwest Territories, RCMP said Wednesday.

The pilot also suffered serious injuries in the crash, which took place late Tuesday afternoon in the Liard mountain range. The pilot was taken by medevac to a hospital in Edmonton.

Air rescue officials with the Joint Rescue Co-ordination Centre in Trenton, Ont., said the pilot ejected from the aircraft as it went down about 25 kilometres west of Nahanni Butte, N.W.T.

Yellowknife RCMP are helping Fort Liard RCMP and Parks Canada staff in recovering the bodies of the two deceased passengers. The helicopter was destroyed in the crash.

"It's a very difficult area to get into — very treacherous cliff faces and loose shale-type footing — so it's going to be an all-day event trying to get the deceased out of there," Staff Sgt. Francis Cullen told CBC News late Wednesday morning.

Cullen said police believe the helicopter was transporting a hunter and guide to the remote mountains from the community of Nahanni Butte, located 500 kilometres southwest of Yellowknife.

The names of the deceased were not released Wednesday, as police notify their next of kin.

The Robinson R44 Raven II helicopter was landing on a ridge top to meet some other hunters and a guide, but the landing didn't work out, according to the Transportation Safety Board.

The aircraft rolled 300 metres down a steep slope, catching fire on impact. Investigators say they can't speculate on how the crash happened or how the pilot escaped.

The Liard Mountains are home to trophy Dall sheep, which attract big-game hunters from across North America.