KABUL, Afghanistan – A NATO helicopter crashed Thursday in southern Afghanistan in an apparent accident that killed six members of the international military force, the U.S.-led coalition said.

The cause of the crash was under investigation, but the coalition said there were no reports of enemy activity in the area at the time. In line with policy, it would not disclose the identities of those killed or their nationalities until the governments and families involved had been notified.

Helicopter-related fatalities and near-misses are not unusual in Afghanistan, although most involve one or two fatalities.

In August, however, in the deadliest single incident in the decade-long war, a military helicopter was shot down in eastern Afghanistan, killing 38 U.S. and Afghan troops, including 17 with the elite Navy SEALs unit that killed al-Qaida leader Osama bin Laden. Seven Afghan commandos also died in that incident.

Thursday’s crash occurred on the same day a suicide attacker detonated an explosives-laden vehicle outside a crowded gate at Kandahar air field, killing seven civilians. Television video showed a scene of carnage, with vehicle parts strewn across the road. The Taliban claimed responsibility and said it was targeting a NATO convoy.

According to two witnesses cited by the Associated Press, the suicide bomber detonated his explosives just as two pickup trucks, which the witnesses said are often used by American special forces, were leaving the base.