Iraqi officials say U.S. forces Wednesday killed six Iraqi security personnel in what the U.S. describes as a case of "mistaken fire".
Authorities say the shooting involved Iraqi police and military personnel in the town of Tarmiyah north of Baghdad.
U.S. officials released a statement saying the incident is "regrettable" and is being reviewed.
Separately, U.S. officials say coalition forces struck at an al-Qaida network Wednesday, killing one suspect and detaining eight others.
A military statement says troops killed a man who was trafficking rockets and bomb components for a terrorist cell based in Tikrit.
On Tuesday Iraqi insurgents carried out three bomb attacks, killing eight people and wounding 20 others.
In the deadliest attack, the U.S. military says a car bomb exploded near an Iraqi army checkpoint in the northern city of Mosul, killing four civilians.
Insurgents also set off two roadside bombs in the capital, Baghdad, killing four people. One bomb exploded near a hospital in the center of the capital, while the other went off in a western district.
Some information for this report was provided by AFP and Reuters.
Iraq: US Fires on Iraqi Security, Killing Six