BAGHDAD — Clashes apparently spurred by Wednesday's bombing of a sacred Shiite Muslim shrine claimed the lives of at least four people in Basra on Thursday and sparked protest marches in Baghdad's Sadr City area and in the Shiite holy city of Najaf.
But curfews and military patrols kept retaliatory violence well below the levels seen last year after the same mosque was bombed. Only five bodies were found dumped in Baghdad's streets.
As many as a dozen mortars or rockets rained onto the capital's heavily fortified Green Zone Thursday afternoon, causing an unknown number of casualties.
Speculation ranged widely over who was behind the toppling of two minarets at the al Askariyah Mosque in Samarra, where the February 2006 destruction of the shrine's golden dome fueled a surge in reprisal killings that left thousands dead.
U.S. officials blamed al Qaida in Iraq for Wednesday's blast. But others questioned that explanation, noting that the security force assigned to the building is known for its strong ties to the Mahdi Army militia of Shiite cleric Muqtada al Sadr.
The Iraqi government has detained at least a dozen men who ostensibly were involved in guarding the Askariyah shrine. Those on guard initially reported that the damage came from mortar fire. But the destruction of the narrow minarets was too complete and too precise to be caused by mortar rounds.
Government officials said regional police were in charge of providing an outer ring of security. Those closest to the shrine, said an Interior Ministry spokesman, were Sunni members of the Facilities Protection Service, or FPS.
Yet that raised questions about why a uniformed force dominated by Shiites would choose Sunnis to be the last line of defense at a Shiite shrine.
The armed men of the FPS are lightly trained and poorly regarded, even by Iraqi standards. FPS guards were standing watch last month at a Baghdad government building when kidnappers took five Britons without resistance. The five are still missing.
A Samarra police official, speaking on condition of anonymity because he wasn't authorized to release the information, said that a new protection force arrived in the city two days before the bombing and quarreled with the guards it was replacing.
The official said that on Tuesday, the day before the bombing, the guards ordered shop owners on a street leading up to the shrine to close their businesses and leave the area.
In its report last year, the Iraq Study Group, chaired by former Republican Secretary of State James Baker and former Indiana Democratic congressman Lee Hamilton, said FPS units have "questionable loyalties and capabilities," are often referred to by Iraqis derisively as militias and provide "funding and jobs for the Mahdi Army." Mahdi forces battled American troops in 2004, and are widely considered responsible for widespread killing of Sunnis.
On Thursday afternoon, thousands took to the streets of the Sadr City section of east Baghdad to protest the Samarra attack. Shortly before sundown, sound trucks moved through the Mahdi Army stronghold calling for Shiites to prepare to protect what the government had failed to guard.
The enclave of roughly 2 million provides Sadr's political base.
Sadr called on the 30-lawmaker bloc he controls to boycott parliament in protest. This spring, six members of the Iraqi cabinet loyal to Sadr quit when the government refused to set deadlines for U.S. troop withdrawals from Iraq. Those cabinet posts remain unfilled, though U.S.-backed Prime Minister Nouri al Maliki last month selected people for them.
Sadr's only public statements since Wednesday's bombing called for peace and didn't blame Sunnis for the Samarra blast. Instead, he blamed the government and American troops for failing to prevent the attack.
In Sadr City, members of the Mahdi Army cruised otherwise abandoned streets Thursday evening — four gunmen to a car — and shooed civilians back into their homes. U.S. troops also made highly visible patrols throughout Baghdad in an effort to keep order.
Lt. Col. Christopher Garver, a spokesman for the U.S.-led forces, said Americans might provide forensic expertise to the Samarra bombing investigation. But he said that Iraqis were leading the probe.
John Negroponte, the second-ranking official in the U.S. State Department, was visiting the Green Zone when it was hit by mortars or rockets.
Negroponte said the Samarra bombing employed some of the same tactics that destroyed the golden dome last year. He called it a "deliberate attempt by al Qaida to sow dissent and inflame sectarian strife among the people of Iraq."
The U.S. blamed al Qaida for last year's blast, as well, though no group has taken responsibility for either attack.
Meantime, a scattered handful of Sunni mosques came under attack following the Samarra bombing.
Someone planted explosives in the Hateen mosque in Iskandariyah some 30 miles south of Baghdad that created a fire before dawn Thursday. Two people living nearby were wounded and the mosque was ruined.
Another Iskandariyah mosque, al Mustafa, was attacked by gunmen who were repelled by Iraqi soldiers.
Gunmen shot at the al Basheer mosque in Mahaweel at about 6 a.m., routed guards there and set the building on fire.
Farther south in Basra, police reported that four people died and six were injured in attacks on four mosques.