BAGHDAD — The bombing of a major Shiite shrine Wednesday has stoked fears that a full-scale civil war may erupt in Iraq and sharpened long-standing animosities between Shiite and Sunni Muslims across the Middle East.
The dawn attack on the Golden Mosque in Samarra also undermined America's political goals at a critical juncture when U.S. envoys are struggling to keep a delicate nation-building process from disintegrating into outright religious warfare.
"The situation has gravely deteriorated," Ashraf Jehangir Qazi, the United Nations' special representative to Iraq, said in an interview after the explosion set by unknown assailants. "It is precisely what can very dangerously inflame the sectarian situation."
The blast that blew the dome off one of the holiest Shiite sites in the world is expected to embolden Iraq's Shiite militias just as Washington was trying to purge them from the nation's security services and keep them off the streets. Shiite political parties were strengthened by the attack, at a time when the U.S. Embassy in Baghdad has been prodding Sunni Arabs, Kurds and secular Iraqis to form a counterweight to the long-repressed majority sect's newly minted political power.
The attack, which could also strengthen the influence of neighboring Shiite-ruled Iran, fanned the flames of sectarian tension anew, promising to further entangle the U.S. military in Iraq.
"It will incite some bitter feelings within the Shiite communities, and it will also instigate some sectarian frictions between Sunni and Shiite," said Saad Jawad Qindeel, a moderate Shiite politician.
Within hours, retaliatory attacks targeted the minority Sunni population, which had been favored until President Saddam Hussein was toppled from power in the 2003 U.S.-led invasion.
Wednesday's bombing and counterattacks threatened to undo efforts by American forces to stave off civil war and regional conflict.
Armed, black-clad Shiite militiamen swarmed the streets of Baghdad and other cities, waving AK-47s and rocketpropelled-grenade launchers, quickly unsettling two years of efforts to rein in these armed groups. Some reportedly fired rockets and machine guns at Sunni mosques, heightening Sunni Arabs' worries about the threat that Shiite militias pose to their communities.
The mayhem left more than 60 Iraqis dead.
The growing power of the politically tied militias, some of which are indistinguishable from official Iraqi security forces, has proved a difficult issue to resolve in efforts to stabilize the country.
In recent months, Americans had been making some headway in persuading Shiite officials of the need to remove those with ties to militias from positions of power. But on Monday, even the office of Grand Ayatollah Ali Sistani, the normally restrained unofficial leader of the country's 16 million Shiites, suggested that "the faithful" take up security matters if the government was unable to prevent violence by Sunni-led insurgents.
"The Iraqi government now is supported more than ever, and if its security apparatuses are not able to offer the required security, then the faithful must be able to do it, with the help of God," said a statement released by Sistani's office in the Shiite shrine city of Najaf.
The Samarra bombing dealt American officials in Baghdad a strong blow in their attempts to encourage a broad-based government. For weeks, U.S. Ambassador Zalmay Khalilzad and other embassy officials have been pressuring Shiites to make political concessions, such as removing an unpopular interior minister, to appease Sunni Arabs.
But the Wednesday morning attack bolsters hard-liners within the Shiite camp who consider giving up important posts and softening policies akin to rewarding terrorism. Abdelaziz Hakim, leader of an influential Shiite political party, said that Khalilzad shared part of the blame for the bombing by making remarks that he said gave aid and comfort to insurgents.
"His statement gave the green light to the terrorist groups, and therefore we blame him for part of what happened," Hakim said at a televised news conference.
The attack also drew Iran into the picture, despite recent American calls for Tehran to stay out of Iraq's affairs. Iran, with a 90% Shiite majority, views itself as the worldwide guardian of the sect's affairs, and the bombing drew immediate responses from the country's political and religious leaders.
In Qom, a Shiite seminary city in Iran, Ayatollah Makarem Shirazi, a high-ranking cleric, cast the attack as an attempt to deprive Iraq's majority sect of its recent success in parliamentary elections.
"The occupiers and enemies of Iraq after their failure in the elections there have committed this grave crime in order to create civil war," he said, according to Iranian state radio.
The flaring up of religious violence comes at a moment when sectarian relations are particularly delicate not only in Iraq, but across the region.