A Briton, five Americans and a Canadian died when a Chinook helicopter was apparently shot down in Afghanistan’s most volatile province.
The Taliban claimed responsibility for Wednesday night’s attack.
Nato’s International Security Assistance Force said other troops rushing to the scene were ambushed and had to call in air support to drive off their attackers.
Initial reports suggested the helicopter was hit with a rocket-propelled grenade, said a US official, who spoke anonymously. Nato said there were no survivors.
A purported Taliban spokesman, Qari Yousef Ahmadi, claimed in a phone call to The Associated Press news agency that militants shot the helicopter down in southern Helmand province, the world’s largest opium poppy-growing region where combat has been heavy in recent months.
Ahmadi did not offer any proof for his claim, but he specified the helicopter crashed in the Kajaki district hours before Nato reported that information.
Kajaki is the site of a hydroelectric dam and the scene of recent fighting.
Nato said the CH-47 Chinook was carrying a crew of five and two military passengers when it crashed. The cause was “being determined by military officials”, it said.
According to a US military official, the British and Canadian soldiers were passengers on the helicopter.
Nato said troops going to the crash site were ambushed by enemy fighters and the unit called in an air strike “to eliminate the enemy threat”. It did not say if the troops were from the US-led coalition, Nato’s force or the Afghan army. One civilian was injured by gunfire.