The U.S. military says Iraqi and coalition troops have killed four al-Qaida militants and captured 58 others in a battle in northwestern Iraq.

The military says Sunday's fighting in the province of Ninewah also killed four Iraqi soldiers. Six other Iraqi troops and a coalition soldier were wounded.

Elsewhere, gunmen killed seven Shi'ite men in the town of Madain south of Baghdad Sunday as they walked to the capital for a religious festival.

In another development, the U.S. military has acknowledged that American soldiers killed three Iraqi civilians last month after firing on a speeding car near Baghdad's airport.

Military investigators blamed the June 25 shooting on misunderstandings and said neither the U.S. troops nor the civilians in the car were at fault.

The U.S. military initially said its troops fired on a car carrying suspected militants who sped toward a U.S. convoy on a road to the airport. It said the soldiers believed that someone in the car was firing at them and that Iraqi forces later found a weapon in the vehicle.

The military now says investigators concluded that no weapons were in the car and that its occupants were "law abiding Iraqi citizens." It says the U.S. soldiers opened fire on the car because it approached their convoy at high speed and ignored warnings shots to stop.

The military expressed deep regret and promised "corrective measures" to avoid similar incidents.

Meanwhile, the U.S. military says its troops detained five al-Qaida militants in and around Baghdad and the northern city of Mosul on Sunday. It says U.S. forces also captured three Iranian-backed militants in the capital.

Also Sunday, a bomb blast in the western Iraqi city of Fallujah wounded a senior Sunni politician and killed two of his bodyguards.