Afghanistan ? A helicopter carrying international troops crashed in a rugged section of southern Afghanistan, killing nine service members in the deadliest such incident in four years for coalition forces.

A “large number” of Americans were among the dead, according to a senior military official in Washington, who spoke on condition of anonymity. The official was not authorized to discuss the matter publicly.

One other coalition service member, an Afghan National Army soldier and a U.S. civilian were wounded in Tuesday’s crash.

The coalition would not disclose the helicopter’s mission, and the cause of the crash was not immediately clear. NATO said there were no reports of enemy fire in the early morning hours in the Daychopan district of Zabul province, where the crash took place.

Taliban spokesman Qari Yousef Ahmadi told The Associated Press by telephone that insurgents shot down the helicopter. But the Taliban often exaggerate their claims and sometimes take credit for accidents.

“The Taliban are not involved in this crash at all,” said Mohammad Jan Rasoolyar, a spokesman for the provincial governor in Zabul.

“The investigation is still going on, but the military told us that the helicopter crashed due to technical problems.”

Another coalition service member died following a separate explosion in southern Afghanistan, the coalition said. No further details were available.