Indian air force helicopter crash kills seven

File photo of an Mi-17 V5 helicopter, acquired by the Indian air force from Russia

An Indian air force helicopter has crashed in the north-eastern state of Arunachal Pradesh, killing seven military personnel.

The crash took place at around 06:00 local time (00:30 GMT) when the Russian-made helicopter was on a maintenance mission.

Five air force crew members and two personnel of the Indian army died in the crash, the army said.

Rescue teams are at the crash site in Tawang near the India-China border.

An inquiry has been ordered into the accident.

Tawang is a strategically important border district and came briefly under Chinese control during the 1962 war between the neighbouring countries.

While the Mi-17 V-5 is among the most sophisticated military transport helicopters, India's ageing air force fleet is often blamed for the high number of air crashes there.

More than 170 helicopter and plane pilots have died over three decades, AFP reports.

The air force is investing billions of dollars to replace older aircraft, but the procurement process has suffered delays.