Starting about 6:15 a.m., nearly 10 blasts could be heard in the sprawling area along the Tigris River that houses the U.S. and British embassies, the Iraqi government headquarters and thousands of American troops.
Maj. Brad Leighton, a U.S. military spokesman, confirmed the Green Zone was hit by indirect fire
- the military's term for a rocket or mortar attack - but could not immediately provide more details.
It was the fourth time this week that U.S. outposts in Baghdad appeared to be the targets of rocket or mortar attacks, killing at least six people and wounding both Iraqis and Americans, including at least two U.S. troops.
The flurry of attacks has followed a substantial lull in such assaults as security has increased and violence around the capital has dropped over the last half-year.
Earlier in the week, the U.S. military blamed Iranian-backed Shiite militias that have broken away from al-Sadr's block for the rocket attacks. Tehran denies that it sponsors extremists in Iraq.
As the U.S. praised al-Sadr for extending his cease-fire it also pledged to pursue the breakaway militias, which it calls "special groups."
"Those who dishonor the Sadr pledge are regrettably tarnishing both the name and the honor of the movement," it said.
Separately, the head of the Iraqi Journalists Union was shot Saturday.
Union chief Shihab al-Timimi was attacked by gunmen, police and union officials said, as he was being driven to an art gallery in Waziriya, near central Baghdad. He had just left the nearby headquarters of the union.
AP Television News footage showed him with what appeared to be a gunshot wound to the chest and bandaged shoulders and arms. Al-Timimi, who is in his mid-70s, was elected president of the union in 2004.