Pat Dollard | Young Americans

BAGHDAD (AP) - 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.

Nobody claimed responsibility for the Baghdad attacks, but U.S. commanders have blamed what they call Iranian-backed rogue militia groups for launching missiles against American forces.

The strikes occurred despite a strong push by the U.S. military to prevent militants from using suspected launching sites on the southern edge of Sadr City, the Baghdad stronghold of the Mahdi Army of anti- U.S. cleric Muqtada al-Sadr.

The surge in violence came as tensions rose in Shiite areas despite al-Sadr’s March 30 cease-fire order, which eased nearly a week of fighting in Baghdad, Basra and other cities in the Shiite south. The cleric stopped short of asking his fighters to surrender their weapons, and sporadic clashes have continued.

Al-Sadr has called for a “million-strong” anti-U.S. demonstration on Wednesday in Baghdad to protest the fifth anniversary of the capture of Baghdad by invading U.S. troops.

At the edge of Sadr City, Lt. Col. Dan Barnett, the commander of the 1st Squadron, 2nd Stryker Cavalry Regiment, said Iraqi forces had come under sustained fire overnight after establishing checkpoints deeper into the Shiite district.

“They’re working to establish control,” he said, speaking to a small group of reporters as heavy gunfire resounded outside a joint U.S.- Iraqi base on the southern rim of Sadr City.

Mortar shells also fell on a popular commercial area in the Jamila neighborhood, setting a fire that burned some 100 shops, according to the Baghdad military command. It said fire fighters came under heavy gunfire that slowed their efforts to extinguish the flames.

A local fire official, who declined to be identified because he wasn’t supposed to discuss the issue, said the mortars had been aimed at a U.S.-occupied police station but fell short. That report could not be independently verified.

Last week, Prime Minister Nouri al-Maliki, himself a Shiite, ordered a nationwide freeze on Iraqi raids against Shiite militants, bowing to demands by al-Sadr who had hinted at retaliation if Iraqi security forces continue to arrest his followers.

U.S. commanders said they will fight back in order to maintain control of a swath of territory on the southern edge of Sadr City that has been used as a launching site for rockets aimed at the Green Zone, which has come under steady fire since the current tensions began.

“Where we have criminal elements that are threatening the security and peace of the people of Iraq, we take action,” said Maj. Gen. Jeffery Hammond, the top commander of U.S. forces in Baghdad.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP’s earlier story is below.

BAGHDAD (AP)—The U.S. military says a rocket attack on the U.S.- protected Green Zone has killed two American soldiers and wounded 17 people.

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.