A large explosion early Wednesday in Samarra heavily damaged the 101-year-old golden dome of one of Iraq's most famous Shiite religious shrines, sending protesters pouring into the streets. It was the third major attack against Shiite targets in as many days.
Police believe an unknown number of people may have been buried under the debris from the 6:55 a.m. explosion at the Askariya mosque. The shrine contains the tombs of two revered Shiite imams, both descendants of the Prophet Muhammad.
Tradition says the shrine, which draws Shiite pilgrims from throughout the Islamic world, is near the place where the last of the 12 Shiite imams, 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 is still alive and will return to restore justice to humanity. An attack at such an important religious shrine constitutes a grave assault on Shiite Islam at a time of rising sectarian tensions in Iraq.
National Security Adviser Mouwafak al-Rubaie said armed men wearing special forces uniforms broke inside the shrine and seized the guards, including policemen, responsible for protecting the site. The gunmen planted the explosives and fled, he said.
In an interview with the Al Arabiya television network, Al-Rubaie blamed extremists represented by the al Qaeda terror network and the Sunni militant group Ansar al-Sunnah for the explosion, which he says are intended to "to pull Iraq toward civil war."
Thousands of demonstrators gathered near the shrine, waving Iraqi flags, Shiite religious banners and copies of the Muslim holy book, Quran. Shiite leaders in Baghdad's Sadr City neighborhood called for demonstrations against the blast.
"This criminal act aims at igniting civil strife," said Mahmoud al-Samarie, a 28-year-old builder who was among the crowd in this city 60 miles north of Baghdad. "We demand an investigation so that the criminals who did this [will] be punished. If the government fails to do so, then we will take up arms and chase the people behind this attack."
In other recent developments: A roadside bomb exploded Wednesday near a primary school in a mostly Shiite area in southern Iraq, killing two boys and injuring four others. It happened at about 7:45 a.m. in the Bashrogiya area near Kut, 100 miles southeast of Baghdad. Tuesday, a car bomb exploded on a street packed with shoppers in a Shiite area of Baghdad, killing 22 people and wounding 28, police said. It was the deadliest bomb attack in the Iraqi capital in a month. The car bombing occurred shortly before 5 p.m. in a Shiite corner of Dora, a predominantly Sunni Arab district of Baghdad and one of the most dangerous parts of the city - rocked almost daily by bombings, ambushes and assassinations. At least eight other people were killed and more than 30 injured Tuesday in bombings and shootings elsewhere in Baghdad and in attacks on beauty parlors and liquor stores - symbols of Western influence - in Baqouba northeast of the capital. Reporters Without Borders said it was launching a weeklong international campaign for the release of kidnapped American reporter Jill Carroll and two abducted Iraqi journalists, Rim Zeid and Marwan Khazaal. Carroll's kidnappers have set Sunday as the new deadline for meeting their demands, which have not been publicized yet. In eastern Baghdad, Iraqi Migration Minister Suhaila Abed Jaafar escaped injury when a bomb exploded near her convoy, police said Tuesday. Three security guards were wounded. Late Monday, in the northern town of Beiji, several men wearing Iraqi army uniforms kidnapped Fares Abdul-Nabi, an engineer at Iraq's largest oil refinery, police said.Iran is in Iraq, Khalilzad said Monday. He also criticized Iran for demanding that British forces immediately withdraw from the southern Iraqi city of Basra. The demand was made Feb. 17 by Iranian Foreign Minister Manushehr Mottaki while on a visit to Lebanon.
© 2006 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.