BAGHDAD - In a bold blow to Iraqi hopes for peace, suspected al-Qaida bombers toppled the towering minarets of Samarra's revered Shiite shrine on Wednesday, adding new provocation to old wounds a year after the mosque's Golden Dome was destroyed.
The attack stoked fears of a surge in violence between Muslim sects. Prime Minister Nouri al-Maliki's government rushed to contain Shiite wrath against Sunnis: It clamped a curfew on Baghdad and asked for U.S. troop reinforcements in Samarra, 60 miles north of here, and for a heightened American military alert in the capital.
But sketchy reports of sectarian strife began to come in. Police told of at least four Sunni mosques in Baghdad and south of the capital attacked by arsonists and bombers, and of a smaller Shiite shrine bombed north of here.
Wednesday's Samarra attack also threatened to deepen Iraq's political crisis, as the 30-member bloc of radical Shiite cleric Muqtada al-Sadr immediately suspended its participation in parliament in protest.
The Golden Dome bombing in February 2006, at one of Iraqi Shiism's holiest sites, unleashed a bloodbath of reprisals - of Shiite death-squad murders of Sunnis, and Sunni bombing attacks on Shiites. At least 34,000 civilians died in last year's violence, the United Nations reported.
Wednesday's stunning attack came in near-simultaneous explosions at about 9 a.m., completely bringing down the two slender golden minarets, 100 feet tall, that had flanked the dome's ruins. No casualties were reported.
How the attackers evaded the Askariya shrine's guard force, strengthened considerably after the 2006 bombing, was a mystery.
Al-Maliki said policemen at the shrine were detained for questioning, and the Interior Ministry said members of "a terrorist group" - in addition to the policemen - were arrested in Samarra and were being interrogated in connection with the shrine attack.
The Wednesday morning blasts shook the Tigris River-side city of Samarra, sending a cloud of dust billowing into the air, said Imad Nagi, a storeowner 100 yards from the shrine. "After the dust settled, I couldn't see the minarets any more. So, I closed the shop quickly and went home."
Nearby blacksmith shop owner Farouq al-Samaraie said, "I didn't expect there would be another explosion at Askariya mosque because it was already attacked last year."
Resident Abdul-Khali Mohammed predicted violence in the capital: "The Shiite militias now will seize this opportunity to kill Sunni families in Baghdad."
An indefinite curfew was immediately imposed on Samarra, and, as Iraqi army and police reinforcements and U.S. troops poured in, the streets emptied by midafternoon, witnesses said.
A few hundred U.S. soldiers had been stationed around Samarra but had left shrine security to Iraqi forces.
In Baghdad, the prime minister ordered an indefinite curfew, beginning at 6 p.m. Wednesday, on vehicle traffic and large gatherings in the capital.
An official close to the prime minister, citing intelligence reports, said Wednesday's bombing was likely the work of al-Qaida, whose militants have recently moved into Samarra from surrounding areas.
A U.S. statement, from Ambassador Ryan Crocker and U.S. Iraq commander Gen. David Petraeus, unequivocally blamed al-Qaida, saying the terror group sought "to sow dissent and inflame sectarian strife."
Such an attack by the Sunni extremist group al-Qaida in Iraq, increasingly at odds with more nationalist Iraqi insurgents, might have been intended to provoke Shiite retaliation that would help reunite various Sunni elements.
Asked about the meeting in which al-Maliki's office said he asked Petraeus for U.S. reinforcements in Samarra and a stepped-up alert here, U.S. military spokesman Lt. Col. Christopher Garver said only that the command was "obviously very concerned about this and our primary goal is to prevent any violence of the kind that broke out after the last bombing."
Last year's surge in execution-style killings, largely blamed on Shiite militias, had begun to decline in Baghdad in February, at the start of a major U.S.-Iraqi security push to pacify the city. But violence has been on the rise elsewhere in Iraq and the Baghdad numbers have begun to rise again.
The al-Maliki aide and other Iraqi officials spoke on condition of anonymity, either because of the sensitivity of the matter or because they were not authorized to deal with the media.
In a nationally televised address, al-Maliki said he had ordered security forces to bolster protection of religious shrines and mosques across Iraq. The Shiite prime minister also warned against reprisal sectarian attacks.
In Shiite southern Iraq, the reaction to Wednesday's attack was swift. In Najaf, radical cleric al-Sadr called for a three-day mourning period and peaceful demonstrations to mark the minarets' destruction.
He criticized the government for not doing enough to protect the site, and said the U.S. occupation is "the only enemy of Iraq" and "that's why everyone must demand its departure," or a timetable for its departure.
Later, in Baghdad, the 30-member Sadrist bloc in parliament issued a statement saying it would boycott the 275-seat house until the government takes "realistic" steps to rebuild the Askariya shrine.
The action by the Sadrists, whose support for al-Maliki has recently waned, is likely to weaken the Shiite-dominated government and delay adoption of a series of laws needed to build national reconciliation in Iraq.
Iraq's top Shiite cleric, Grand Ayatollah Ali al-Sistani, issued a statement calling on "believers to exercise self-restraint and avoid any vengeful act that would target innocent people or the holy places of others."
In neighboring Shiite Iran, which has been accused of funding and arming Shiite militias in Iraq, President Mahmoud Ahmadinejad blamed U.S. forces for failing to prevent the mosque attack, and threatened to halt regional cooperation to stop Iraq's spiraling violence.
Last year's destruction of the Askariya shrine's dome was also blamed on Sunni Muslim militants believed linked to al-Qaida.
The mosque contains the tombs of the 10th and 11th imams - Ali al-Hadi, who died in 868, and his son Hassan al-Askari, who died in 874. Both are descendants of the Prophet Muhammad, and Shiites consider them to be among his successors.
The shrine also is near the place where the 12th imam, Mohammed al-Mahdi, disappeared. Al-Mahdi, known as the "hidden imam," was the son and grandson of the two imams buried in the Askariya shrine. Shiites believe he will return to Earth to restore justice to humanity.
In other violence Wednesday, a suicide bomber blew himself up at a police station near the Iranian border, killing five Iraqi policemen and wounding 10, the town's mayor said. In the western city of Ramadi, a suicide bomber killed four policemen at a checkpoint, police said.
In northern Iraq, militants blew up part of a bridge in the country's fourth bridge attack in as many days, police said.
The bombing targeted the Zikaytoon overpass southwest of Kirkuk, 180 miles north of Baghdad. The attackers planted explosives under the bridge, and the blast went off around 6 a.m., said police Brig. Sarhat Qader. No one was injured, Qader said.
The state-owned al-Sabah newspaper reported its editor-in-chief, Flayeh Wadi Mijdab, had been kidnapped. Unknown gunmen ambushed Mijdab in eastern Baghdad on Wednesday morning as he was heading to work, police said. His 25-year-old son and driver were left behind, police added.