A U.S. official, speaking on condition of anonymity because the official was not authorized to release the information, said those injured included an American and four third-country nationals, meaning they were not American, British or Iraqi.

Iraqi police said 10 civilians were killed and more than 20 were injured in rocket or mortar blasts in scattered areas of eastern Baghdad — some of them probably due to misfired rounds.

Also in the capital, seven people were killed and 14 wounded in a suicide car bombing Sunday in the Shiite area of Shula in the capital, police reported. Such attacks are the hallmark of Sunni religious extremists.

Gunmen opened fire on passengers waiting for buses in a predominantly Shiite area in southeastern Baghdad, killing at least seven men and wounding 16 people, including women and children, according to police.

Police also found the bullet-riddled bodies of 12 people — six in Baghdad, four in Mosul and two in Kut, scene of clashes between government troops and Shiite militiamen.

No group claimed responsibility for the Green Zone attacks, but suspicion fell on Shiite extremists based on the areas from which the weapons were fired.

The attacks followed a series of clashes last week between U.S. and Iraqi forces and factions of the Mahdi Army, the biggest Shiite militia loyal to radical cleric Muqtada al-Sadr.

Al-Sadr led two uprisings against U.S.-led coalition forces in 2004. Last August he declared a six-month cease-fire to purge the militia of criminal and dissident elements.

U.S. officials have cited the truce, which al-Sadr recently extended, among the reasons behind a 60 percent drop in violence since President Bush ordered 30,000 U.S. reinforcements to Iraq early last year.

But the cease-fire has come under severe strains in recent weeks. Al-Sadr's followers have accused the Shiite-dominated government of exploiting the cease-fire to target the cleric's supporters in advance of provincial elections expected this fall.

Al-Sadr recently told his followers that although the truce remains in effect, they were free to defend themselves against attacks. Al-Sadr followers have demanded the release of supporters rounded up in recent weeks.

U.S. officials have insisted they are not going after Sadrists who respect the cease-fire but are targeting renegade elements, known as special groups, that the Americans believe have ties to Iran.

But the pattern of the attacks against the Green Zone could be a signal to the Americans and their Iraqi partners to ease their pressure against mainstream Sadrists or the special groups.

Elsewhere, 12 gunmen were killed Sunday in a raid against a suspected suicide bombing network east of Baqouba, the U.S. military said.