Beirut: A Lebanese military helicopter crashed while on a routine training mission yesterday in eastern Lebanon, killing all four soldiers on board, a senior Lebanese military official said.

The official, speaking on condition of anonymity, said the helicopter crashed into a mountain near the village of Niha in eastern Lebanon's Bekaa Valley, about 55 kilometres east of Beirut. But the official did not say what caused the incident, only that an investigation was underway.

The crashed helicopter was an American-made Bell 205, one of 16 Bell helicopters belonging to Lebanon's air force, the official told AP.

The army command identified the victims as air lieutenants Hadi Sadaka and Albert Moussalam, air warrant officer Raymond Aziz and private Nizar Obaid. It said the four belonged to the air force. "Contact with the military helicopter was lost at 10.25 am while it was on a training mission," the military said in a statement faxed to AP. "It appeared that the helicopter was subjected to an air accident that caused it to crash over the Niha-Bekaa hills which resulted in the death of the plane's crew." It added that a military committee has started an investigation.

Lt.-Col. George Sadaka, father of Hadi Sadaka, died when his helicopter crashed into the Mediterranean in 1988, the military official said.

Official National News Agency said the helicopter might have experienced "a technical fault" that caused the crash. It quoted its correspondent in the area as saying fire engulfed the aircraft after it crashed.