"The checkpoint was attacked last night. Then the police started fighting with the Americans. Whether they attacked the Americans willingly, we don't know," Mr. Gilani said.
Military: Afghan inside attack kills 4 U.S. troops →
It was not clear if some of the Afghan police turned on their American helpers in the middle of the battle with the insurgents, or afterward, or were somehow forced into attacking the American troops by the insurgents, Mr. Gilani said.