asdfgaKABUL: Two Americans were killed in the latest attack by a member of the Afghan security forces, as US military deaths reached or neared 2,000 since the start of the war in Afghanistan in 2001.

A US official, who asked not to be identified, confirmed on Sunday that an American soldier and a civilian contractor were killed in Saturday's attack in eastern Afghanistan.

It was the latest setback 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 on the NATO-led International Security Assistance Force (ISAF) by its Afghan allies. At least 52 ISAF service members have been killed this year in “green-on-blue" attacks.

Pentagon data on a Defense Department website put total US deaths in the Afghanistan war at or close to 2,000 since combat began 11 years ago.

It was too early to say what impact the latest incident would have on plans to restore joint operations with Afghan troops to normal, a spokesman for ISAF said.

The attack took place in the Sayed Abad district of the Wardak province, according to local police sources, who said a gun battle broke out between coalition soldiers and Afghans when an Afghan National Army member opened fire on American troops.

Three members of the Afghan National Army were also killed in the firefight, while three other US citizens and one Afghan were wounded, police spokesman Wali Mohammad said on Sunday.

“We appreciate the sacrifice of our fallen heroes, every death is tragic and important none more than any other," ISAF said in a statement after Saturday's attack.

Copyright Reuters, 2012