4 U.S. Troops Killed in Another 'Insider' Afghan Police Officer Attack

Four American troops were killed in southern Afghanistan early Sunday after a man dressed as an Afghan police officer turned his gun on them at a remote checkpoint, officials said.

The Americans were part of the NATO-led alliance working to train local Afghan forces, the Associated Press reported. It was the third such "insider" attack against NATO forces in as many days, including one Friday in which two U.S. Marines were killed. Two British troops were shot dead Saturday.

Two other international troops were also wounded in Sunday's attack, Reuters reported. One of the six members of the Afghan National Police was found dead at the scene, and the other five were missing.

"The attack took place in the vicinity of an outpost in southern Afghanistan. It is my understanding that it was a checkpoint," NATO forces spokesman Jamie Graybeal told the AP. He said the dead Afghan police officer was killed in the clash with troops and it was unclear whether those missing from the scene were involved or not.

Deputy Afghan police chief for the province Ghulam Gilani told the AP the checkpoint first came under attack from insurgents around midnight and that the troops came to help Afghan police respond.

"The checkpoint was attacked last night. Then the police started fighting with the Americans. Whether they attacked the Americans willingly we don't know," Gilani said.

A Taliban spokesman told the AP the police who attacked the Americans were not associated with the Taliban, "but they are Afghans and they know that Americans are our enemy."

The spokesman claimed the missing officers had joined up with the Taliban.

NATO said the situation was under further investigation