Baghdad, Iraq ? A mortar attack killed two American soldiers and wounded four others Friday at an outpost north of Baghdad, and a third American died in a gunbattle in the northern city of Mosul, the U.S. military said.

The mortar attack occurred about noon at a 4th Infantry Division forward operating base near Samara, 70 miles north of Baghdad, the U.S. Central Command said.

It was the second mortar attack against a 4th Infantry Division position in as many days.

Late Thursday, 13 soldiers from the division were wounded when a mortar struck a hangar at the U.S. Camp War Horse near Baqouba, 40 miles northeast of Baghdad.

The 4th Infantry is responsible for security in a large swath of territory in northern Iraq and has suffered more attacks than any other U.S. command in Iraq, according to American officials in Baghdad.

In Mosul, a soldier from the 101st Airborne Division was killed during a gunbattle before dawn Friday with armed men who attacked a grain storage facility, the military said.

In Fallujah, a center of Sunni Muslim resistance 40 miles west of Baghdad, U.S. soldiers were seen beating and kicking a pair of suspects detained after what witnesses said was a roadside bombing. It was the sixth attack by insurgents in Fallujah in as many days.

Iraqi witnesses said the attack took place near a bridge at the western end of Fallujah. The witnesses said three injured U.S. soldiers were evacuated after American soldiers raked the area with gunfire.

After the attack, television footage showed U.S. troops detaining several Iraqi civilians, with one soldier dragging a man from his vehicle and punching him repeatedly in the abdomen as he fell to the ground. Another soldier could be seen kicking a detainee in the leg before hauling him from the pavement and leading him away.