BAGHDAD, Iraq -- Bombers and gunmen killed more than 110 Shiite Muslim pilgrims observing a religious ritual and wounded more than 250 others in scores of sectarian attacks yesterday that threatened to derail a renewed effort to stabilize Iraq.
In the worst incident, two suicide bombers walking among the pilgrims in the southern city of Hilla detonated their explosive belts within two minutes of each other, killing at least 77 and injuring 127, according to local police. Around Baghdad, gunmen, car bombs and roadside bombs killed at least 35 and injured 137 others.
The attacks came on a day when the U.S. also disclosed the deaths Monday of nine soldiers in roadside bomb attacks on convoys in northern Iraq. Six soldiers were killed in one bombing, and three were killed in another. It was the deadliest day for U.S. troops in Iraq in nearly a month, according to the military.
The soldiers were part of a group called Task Force Lightning based in Tikrit, the birthplace of Saddam Hussein, north of Baghdad. The area is a Sunni insurgent stronghold. Further details were not available.
As sectarian attacks on civilians have escalated in recent days, Iraqi security officials have continued to insist the crackdown will be effective.
"Nothing is difficult or impossible," said Qassim Moussawi, a spokesman for the Baghdad security plan. Once political and law enforcement efforts are fully under way, he said, "Such attacks will be reduced."
But yesterday's attacks on Shiites inflicted one of the heaviest tolls related to a major Shiite holiday since the nascent civil war began.
The annual pilgrimage marks the anniversary of the 40th day after the death of Imam Hussein, a grandson of the prophet Muhammad, who was killed by the Sunni caliph's army in the seventh century during a battle for control over leadership of Islam. In observance of the day, Shiite pilgrims march to the southwestern city of Karbala, where the battle occurred.
Ashura, the annual holiday marking the anniversary of the battle and Hussein's death, as well as the subsequent pilgrimage, were largely suppressed under Saddam Hussein but have achieved more prominence since his fall. At the same time, they have become occasions for aggressive attacks on Shiites: In 2004, about 180 were killed in Ashura attacks, and in 2005, more than 70 were killed.
In the Hilla bombing, Ali Khadum, 26, a member of the Iraqi National Guard who was waiting for a cousin who was part of the pilgrimage, said people froze in shock after the first explosion before stampeding in all directions.
The second explosion, which occurred a short while later, was so powerful that it sent bodies flying into the air and blew the clothing off its victims. Khadum said survivors used pilgrims' banners to cover the bodies.
Christian Berthelsen writes for the Los Angeles Times. Times reporters Saif Hameed, Raheem Salman and Zeena Kareem in Baghdad and special correspondents in Baghdad and Hilla, contributed to this article.