Blast Kills Dozens of Shiite Worshipers in Southern Iraq

The explosion hit a tent where pilgrims were being fed around 8:30 a.m., killing at least 53 people, including several police officers at a nearby checkpoint, and wounding more than 130 others, local officials said.

There were conflicting reports, though, about the cause of the blast. Some officials said it was a roadside bomb, while others said a suicide bomber had attacked the crowd.

The pilgrims were traveling to a mosque in the city of Zubayr, just west of Basra, for the last day of Arbaeen, the solemn holiday at the end of the 40-day mourning period for the death of Imam Hussein ibn Ali, a grandson of the Prophet Muhammad.

Most Shiites typically make pilgrimages to Karbala, where the imam is buried, and millions of visitors from Iraq and other Muslim countries visit for the holiday. But people in southern Iraq who do not have the stamina or time to march to Karbala make a shorter trip to the Khatwa mosque, a holy site in Zubayr.

During the past 10 days, insurgents have unleashed a string of attacks on Shiites as they have made pilgrimages leading up to Arbaeen in what seems to have been an effort to incite sectarian violence during a monthlong political crisis that has increased tensions between the country’s Shiite and Sunni politicians.

So far, though, the attacks do not appear to have turned the political tensions into violence between the sects on the streets. No group has claimed responsibility for the attacks, but they are similar to others conducted by Al Qaeda in Mesopotamia against pilgrims in previous years. A homegrown group with some foreign leaders, Al Qaeda in Mesopotamia says that the Iraqi government is run by apostates, and it hopes to topple the government by plunging the country back into a sectarian war, like the one that engulfed Iraq a few years ago.

“We were only going to visit the mosque,” said a Basra resident, Samir Khadim, 47, on Saturday after the explosion. “What crime did we commit that made them want to kill us? The first thing I thought about when I fell on the ground was my family. The bombings will never stop us from celebrating. We have been doing this for years and will never stop.”

Saturday’s attack was similar to another one mounted by insurgents on Jan. 5. That day, a suicide bomber detonated an explosive vest in a crowd of pilgrims close to a security checkpoint near the city of Nasiriya, just north of Basra, killing 44 and wounding dozens.

In response to the attacks, the Iraqi government increased security for the pilgrims, stationing tens of thousands of security officers throughout the southern part of the country and Karbala.

“We made a security plan two days ago to protect the pilgrims, and we raided a number of houses in the area and found a number of explosive devices and weapons,” said Ali Ghanim, the chief of the security committee for the Basra provincial council.

Mr. Ghanim said the attack on Saturday was carried out by a suicide bomber, a much more difficult type of attack to prevent.

“There was a man who was holding a box and giving food to people, and one of our security officers found him suspicious and went to search the box and the man blew himself up,” he said.

Mansour al-Tamimi, a member of Parliament from Basra, said that protecting the pilgrims was difficult because they walked such long distances.

“There’s a weakness in the intelligence and the security forces, and they do not get information to pre-emptively stop attacks,” he said.

“The main goal of these attacks is igniting the sectarian violence,” he said, “but I don’t think the sectarian violence will return because people know what the insurgents are trying to do.”