An apparent insider attack by Afghan forces has killed a US service member and a foreign civilian contractor with NATO.
The shooting was the latest in a string of attacks on international troops by their Afghan allies and marked the 2,000th US troop death in Afghanistan since 2001.
A US military official confirmed that the service member killed was from the US.
At least two Afghan soldiers were also killed in yesterday's attack at an Afghan army checkpoint in Wardak province, said Shahidullah Shahid, a provincial government spokesman.
An Afghan soldier turned his gun on the US troops and started shooting, Mr Shahid said.
He said the checkpoint was in Sayd Abad district, just outside a joint US-Afghan base.
"Initial reports indicate that a misunderstanding happened between Afghan army soldiers and US soldiers," Mr Shahid said.
He said investigators had been sent to the site to try to figure out what happened. An Afghan military spokesman declined to comment.
Afghan soldiers and policemen, or militants in their uniforms, have shot dead more than 50 foreign troops so far this year, eroding the trust between coalition forces and their Afghan partners.