The nine are all NATO soldiers. Their nationalities are being withheld until their families are notified. Three other survived the crash, including an American civilian and an Afghan soldier.
NPR's Quil Lawrence reports from Kabul that the helicopter went down in the Daichopan district of southern Zabul province, insurgent territory, though NATO officials reported no hostile fire.
These deaths make 2010 the deadliest year in the almost nine year war. 529 international forces have been killed so far this year. American commanders had predicted more casualties as an additional 30,000 American troops arrived in the country and spread out to areas where the Taliban had operated with impunity.