A member of Nato's Afghan force and a civilian contractor have been killed in the latest so-called insider attack by a member of the country's security forces, bringing the US death toll in the conflict up to 2,000.
The attack in eastern Afghanistan on Saturday came after the United States said joint operations with Afghan forces were returning to normal.
Joint operations were halted two weeks ago after a surge of attacks by Afghan allies. At least 52 members of the Nato force have been killed this year in so-called green-on-blue attacks.
It was too early to say what impact the latest incident would have on plans to restore joint-operations with Afghan forces to normal, a spokesman for NATO's International Security Assistance Force said.