All nine people on board a Japanese search and rescue helicopter that crashed into the central mountains have been confirmed dead.

The Bell 412EP helicopter carrying seven local rescue workers from the Gunma prefecture and two from a flight service company lost contact about an hour after take-off on Friday and crashed.

Prefectural officials said the last person on board was retrieved on Saturday and pronounced dead.

The helicopter was on a two-hour flight to monitor the opening of a mountain trail.

Japan Rescue Helicopter Crash
The rescue helicopter prior to the crash (Gunma Prefectural Fire Safety Division/AP)

The prefecture said it cancelled Saturday’s event due to the accident. It was not clear what caused the crash.

An investigation continues at the mountainside crash site, where debris of the helicopter was scattered and trees torn down apparently from the impact of the fall.

Japanese media quoted witnesses as saying the helicopter was flying extremely low in foggy weather before the crash.

The GPS data sent from the helicopter indicated it was making a turn a minute before the transmission stopped, Kyodo News reported. It said the helicopter was not carrying a flight data recorder.

Prefectural officials said the helicopter, which was about 20 years old, had its engine repaired in April but had no abnormality since it resumed operations in June.