June 23, 2007

One of Iraq’s most sacred Shiite shrines, the Imam al-Askari mosque in Samarra, was attacked and severely damaged again today, just over a year after a previous attack on the site unleashed a tide of sectarian bloodletting across the country.

Following the attack, which destroyed the mosque’s two minarets, the Iraqi government announced a curfew in Baghdad starting at 3 p.m. local time today. Shiite leaders called for calm. Grand Ayatollah Ali al-Sistani, the most revered Shiite cleric in Iraq, condemned the bombing, but appealed to Iraqis to show restraint.

It was unclear who carried out the attack in the predominantly Sunni town about 60 miles north of Baghdad. Iraqi security forces secured the area around the mosque and were investigating the cause of the explosion, the American military said. Iraqi police reported hearing two nearly simultaneous explosions coming from inside the mosque compound at around 9 a.m. today.

The official Iraqia television station reported that local officials said that two mortar rounds were fired at the two minarets.

The shrine was badly damaged in the February 2006 attack by Sunni insurgents, but the destruction of the remaining two minarets is expected to have powerful symbolic importance to Iraqis.

Radical Shiite cleric Moktada al-Sadr called for peaceful demonstrations and a three-day mourning period to mark the shrine’s destruction.

In Samarra, where a curfew was in place, there were scattered reports of demonstrations by protesters condemning the attack, though an American military official in the area said that by this afternoon the city of roughly 100,000 was quiet.

A curfew was also in place in Hilla, a mixed area about 50 miles south of Baghdad, where officials said they received word of a possible protest by Shiites.

The American authorities in Iraq blamed the attack on Al Qaeda.

In a joint statement, the American ambassador to Iraq, Ryan C. Crocker, and Gen. David H. Petraeus, the top American commander in Iraq, said: "This brutal action on one of Iraq’s holiest shrines is a deliberate attempt by Al Qaeda to sow dissent and inflame sectarian strife among the people of Iraq."

Senior American military commanders in Iraq have said recently that they feared an imminent dramatic attack from Sunni insurgents to refocus Sunni attention on the country’s struggle between Shiites and Sunnis, and to reunite Sunnis in the wake of American attempts to consolidate Sunni resistance to extremist groups like Al Qaeda of Mesopotamia.

But they expected that if such an attack did occur, it would most likely come at one of Iraq’s three other most-sacred Shiite sites, not the al-Askari shrine, which was already badly damaged.

Since the attack in 2006, the shrine had been under the protection of local — predominantly Sunni — guards. But American military and Iraqi security officials had recently become concerned that the local unit had been infiltrated by Al Qaeda forces in Iraq.

A move by the Ministry of Interior in Baghdad over the last few days to bring in a new guard unit — predominantly Shiite — may have been linked to the attack today.

Speaking on Al Jazeera television, Abdul Sattar Abdul Jabbar, a prominent Sunni cleric, said the new guards had arrived at the shrine shouting sectarian slogans that may have provoked local Sunnis, in a sign that the attack was already being depicted as sectarian.

Gunfire was reported around the mosque last night, which may have been related to the change of guards.

Attacks on Shiite holy sites by suspected Sunni insurgents have increased in Iraq in the last two months.

In April, a car bomb exploded in Karbala about a third of a mile from the Imam Abbas shrine, the second-holiest site in Shiite Islam, killing at least 58 people and wounding 169.

Two weeks earlier in Karbala, another car bomb exploded near the Imam Hussein shrine, killing 36 people and wounding 168.

In both cases, a perimeter of security — with blast walls and Shiite guards — prevented the bombers from getting close enough to the mosques to damage them.

Tensions in Samarra have also risen recently. Last month, a suicide car bomber attacked a police battalion headquarters, killing the police chief and 11 others, the military said in a statement.

The chief, Lt. Col. Abdul Jaleel Hanni, a Sunni former member of Saddam Hussein’s intelligence service, had been respected by the Americans for his ability to recruit officers and maintain discipline.

The attack in 2006 on the al-Askari mosque ravaged the mosque’s dome, which had been the defining feature of the shrine.

Before that attack, more than a million Shiites streamed into the mosque each year, visiting the graves of the 10th and 11th Imams. They also came to honor Muhammad al-Mahdi, who became the 12th Imam when he was only 5 years old, in A.D. 872.

Shiites believe that it was at the shrine that the Mahdi was put into a state of divine hiddenness by God to protect his life. Shiites believe that the Mahdi will return at the end of days, at a time of chaos and destruction, to deliver perfect justice.

John F. Burns and Damien Cave contributed reporting from Baghdad. Employees of The New York Times contributed reporting from elsewhere in Iraq..