The soldier, who wasn't immediately identified, was killed when an unidentified Iraqi walked up to him and opened fire with a pistol, according to senior U.S. Army officers in Baghdad who had heard reports of the shooting.
The officers said the slain soldier belonged to the 2nd Armored Cavalry Regiment from Fort Polk, La. Calls to that regiment's public affairs officer here went unanswered Thursday night.
No further information was immediately available, and it was unclear what happened to the assailant. U.S. Central Command in Qatar said it was unaware of the incident.
U.S. forces report that they trade fire with armed Iraqis almost daily across the country. Still, an incident like Thursday's a brazen daytime attack, apparently at very close range is nonetheless highly unusual even in postwar Iraq.
Elsewhere in Baghdad on Thursday, soldiers with the Third Brigade took fire during a security patrol. They fired back, then called in a psychological operations teams to coax at least some of the assailants into surrendering. No U.S. soldiers were injured.
On Wednesday, the military said, two Iraqis shot at reconnaissance elements of the 3rd Infantry Division with small arms and rocket-propelled grenades as they traveled north of Baghdad. The unit returned fire, the military said, killing one assailant.
Another unit came under fire traveling near Tikrit, returned fire and left the area. There were no injuries.
Also Wednesday, near the northern town of Baiji, a convoy from the 4th Infantry Division came under rifle and machine-gun fire. The unit attacked the assailants' positions and captured five individuals, weapons, and other military, Central Command said. No Americans were injured.
On Tuesday, a Marine patrol was shot at. In the ensuing firefight, no Marines were hurt but they killed one and wounded four. Sixteen people were detained.