The U.S. military says rocket or mortar attacks against the U.S.-protected Green Zone and a military base elsewhere in Baghdad have killed three American service members and wounded 31.

A military official says two U.S. troops were killed and 17 wounded when rockets struck the Green Zone in central Baghdad. The official says another American service member died and 14 were wounded in another attack on a military base in the southeastern area of Rustamiyah.

The official spoke on condition of anonymity for lack of authorization to release the information.

The attacks come amid fierce clashes between Shiite militia fighters and U.S.-Iraqi forces.

A military official says Sunday's casualties occurred when at least two rockets struck the sprawling area in central Baghdad.

The official spoke on condition of anonymity for lack of authorization to release the information.

The Green Zone has faced frequent attacks amid fierce clashes between Shiite militia fighters and U.S.-Iraqi forces.

Nobody has claimed responsibility for Sunday's attack. But the military has in the past blamed Iranian-backed rogue Shiite militia groups for the attacks.

PHOTO CAPTION 

A US soldier patrols a street in Adwaniyah, just south of Baghdad, last month.

AP