BBC News - South Afghanistan plane crash kills four Isaf personnel: "South Afghanistan plane crash kills four Isaf personnel"
spokesman said the cause of the crash was being investigated, but initial reports suggested there was no militant activity in the area at the time.
He did not give the nationalities of the victims or the crash's location.
However, the deputy governor of Zabul province said a foreign military aircraft came down there on Saturday.
Mohammad Jan Rasoulyar told the Associated Press that the scene of the crash in Shah Joy district had been surrounded by troops.
Last month, five US troops were killed when a helicopter crashed during a rainstorm in the southern province of Kandahar.