In an attempt to quell the fighting between Shiite militiamen and security forces, authorities in Baghdad have imposed a weekend curfew on the capital.
An official with the command says no unauthorized vehicles, motorcycles or pedestrian traffic will be allowed on the streets from 11 p.m. Thursday to 5 a.m. Sunday, the Associated Press reports.
The curfew was imposed after clashes in the south have become fierce and after 3 days of mortar and rocket attacks targeted the heavily fortified Green Zone in Baghdad. One American government worker was killed in one of those attacks today, according to the U.S. Embassy.
Defiant Shiites flexed their muscle by sending tens of thousands of supporters into the streets of the capital and holding the Iraqi army at bay in the key oil city of Basra.
Amid all the turmoil, a bomb blasted a crucial oil pipeline in Basra, triggering a massive fire and threatening the country's ability to export oil.
It was the second oil pipeline attacked in southern Iraq this week. Basra's oil accounts for 80 percent of Iraq's production.
The pipeline blast sent the world's price of oil to $107 a barrel.
The growing anger over the government's attempt in Basra to crack down on the forces of anti-American cleric Muqtada al-Sadr threatens to end a truce with the powerful Mahdi Army.
The Madhi Army has twice embroiled U.S. troops in vicious fighting in much of southern Iraq. Another uprising could trigger a virtual civil war and bring into doubt the Bush administration's ability to withdraw U.S. troops.
Sadr's supporters lashed out at the U.S. and the Iraqi government today. Rockets and mortars fired from their Baghdad stronghold of Sadr City showered the Green Zone with rockets and mortar shells for the fourth straight day. One landed next to the U.S. Embassy compound.
Thick, black smoke billowed from inside the heavily fortified home to the U.S. Embassy and Iraqi government, but no injuries were reported in today's barrage. Since the Green Zone attacks have started, however, one U.S. soldier, two American civilians and an Iraqi soldier have been wounded and an American financial analyst has been killed.
Anger over the Basra crackdown has spread across southern Iraq where the Mahdi Army is strongest and is vying for control with government forces as well as rival Shiite groups.
Seventeen deaths were reported in scattered fighting around Sadr City and 60 were killed fighting in the southern city of Hilla.
Mahdi fury is focused on Prime Minister Nouri al-Maliki, a Shiite who is personally overseeing an operation against the militias in Basra. The crisis over the control of Basra is seen as a test of the government's ability to take over security.
Al-Maliki has given the gunmen in Basra an ultimatum to surrender their weapons by Friday or face harsher measures.
Despite the threat, heavy gunfire and explosions resounded across Basra while helicopters and jet fighters buzzed overhead. The city's police chief escaped an assassination attempt late today, but three of his guards were killed in the roadside bombing.
Government troops have faced stiff resistance in neighborhoods controlled by the Mahdi Army in Basra, Iraq's second-largest city, 340 miles southeast of Baghdad. Residents spoke of militiamen using mortar shells, sniper fire, roadside bombs and rocket-propelled grenades to fight off security forces.
A Pentagon official said Wednesday that reports from the Basra area indicate that militiamen have overrun a number of police stations and that it was unclear how well the Iraqi security forces were performing overall. The official spoke on condition of anonymity because he was not authorized to discuss the matter publicly.
Demonstrators in the northern Baghdad neighborhood of Kazimiyah called al-Maliki a "new dictator" as they carried a coffin bearing a crossed-out picture of the U.S.-backed prime minister, who belongs to a rival political party.
A sea of people also rallied in Sadr City, chanting slogans against the government and in favor of al-Sadr.
Sheik Salman al-Feraiji, al-Sadr's chief representative in Sadr City, issued a statement with demands to quell the discontent, including the release of Sadrist detainees, an end to military operations against them and al-Maliki's resignation.
In other news out of Iraq, two American soldiers were killed Wednesday in separate attacks in Baghdad, the military said.
Authorities identified the remains of two more U.S. contractors kidnapped in Iraq and are awaiting forensic testing on the remains of a third body, the FBI said today.
FBI spokesman Richard Kolko identified the two men as Paul Johnson-Reuben of Minneapolis, Minn., and Joshua Munns of Redding, Calif. They were among six Western contractors kidnapped in Iraq more than a year ago.
The case received attention earlier this month when the severed fingers of five of the men were sent to the U.S. military in Iraq.
The Associated Press contributed to this report