U.S. troops fired on two cars at a checkpoint in Fallujah (search), killing four Iraqis and wounding five others, local residents and Arab satellite television reported Saturday.

U.S. military officials could not be reached for comment because their telephone system appeared to be malfunctioning.

Residents reached by telephone in Fallujah said the shootings occurred late Friday on the eastern edge of Fallujah, where opposition to the American presence runs deep. Al-Jazeera (searchtelevision said one of those wounded was a child.

Fallujah, located west of Baghdad in the so-called "Sunni Triangle (search)," is one of the major flashpoints of tension between U.S. troops and Iraqi civilians.

On Sept. 12, U.S. soldiers from the 82nd Airborne Division killed eight Iraqi policemen and a Jordanian hospital guard near Fallujah. The police were chasing a car known to have been involved in highway banditry.

In April, soldiers from the division fired on protesters on two successive days, killing 18 and wounding 78. U.S. troops had withdrawn to a base outside the city in July and had been turning over security duties to local police. The U.S. military at the time said the troops were fired at first in the April incident, but Iraqi witnesses denied this.