Updated

An Afghan policeman opened fire on U.S. troops at a police station, killing an American soldier and wounding three, officials said Monday.

An American commander said U.S. forces in the station in eastern Afghanistan then killed the policeman.

"Initial reports suggest that a rogue ANP (Afghan police) official turned on our forces and shot and killed one of our soldiers, said Col. John "Pete" Johnson, the commander of Task Force Currahee in eastern Afghanistan.

The shooting took place in Paktia province Sunday after American troops and Afghan police brought suspected militants to the station. The policeman wounded three U.S. soldiers, one of the detainees and an Afghan interpreter working for the Americans, officials said.

Three detainees escaped during the confusion, Johnson said. When asked whether the Taliban or another militant group had infiltrated the police, he said it was a possibility.

"I think that's certainly an assumption that you could make but at this point, I can't confirm it," Johnson said. "I don't know what the motivations were for the ANP (Afghan police) to turn on our forces and shoot them and shoot the detainee. Quite frankly this is way out of the norm. ... This is the first incident of its kind."

An earlier statement from NATO's International Security Assistance Force said there was an "altercation" at the station during which an Afghan officer and a NATO soldier were killed. But it did not include any details about how the shooting happened.

That lack of detail angered American commanders, who wanted the incident spelled out clearly.

"The stories I read did not reflect the facts as I know them and I think it's important for the (Task Force) Currahee family back home, to make sure the facts are out there appropriately," Johnson said.

British Capt. Mark Windsor, a spokesman for the NATO-led mission in Afghanistan, said the language in the original news release was agreed on by NATO and Afghanistan's Ministry of Interior, which is in charge of the police.

"In trying to play the incident down, we could have chosen our words better," Windsor said.

The Americans and Afghans involved in the shooting incident were on a joint patrol when they were attacked by a roadside bomb Sunday. No one was injured.

Militants observing the attack then fired at the Americans and Afghans before fleeing. Afterward, military fighter aircraft tracked down the militants, the soldiers apprehended them and tested them for explosives residue, NATO said. The suspects tested positive.

Seven detainees were then taken to the Afghan police station in Paktia, where the Afghan policeman opened fire.