The alliance says in a statement the crash occurred on Tuesday and that it's under investigation. It did not provide any further details nor on the nationalities of the service members on the aircraft.
The U.S.-led international coalition has service members from several countries deployed in the south.
NATO says initial reporting indicated there was no fighting or insurgent activity in the area at the time of the crash.
Deputy governor of southern Zabul province, Mohammad Jan Rasoolyar, says a NATO helicopter crashed in the remote district of Shajau.
It was not immediately clear if he was describing the same incident.
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