BAGHDAD — The U.S. military blamed a renegade Shiite militiaman on Wednesday for a truck bombing that killed 63 people in a Shiite area of Baghdad, saying he was trying to re-ignite sectarian violence for personal gain.
The allegation points to a shift in the Iraq conflict, with the U.S. military increasingly concerned about Iranian-backed Shiite splinter groups as al-Qaida's influence recedes.
No group claimed responsibility for the blast, which devastated a bustling commercial street in Hurriyah, scene of some of the bloodiest Shiite-Sunni slaughter in 2006. That fueled speculation Sunni extremists may have been behind the attack.
However, U.S. spokesman Lt. Col. Steven Stover said the American command believed the bombing was carried out by a Shiite splinter group led by Haydar Mehdi Khadum al-Fawadi, also known as Haydar al-Majidi, who has been sought for months for kidnapping, murder and other offenses.
"We believe he ordered the attack to incite (Shiite) violence against Sunnis; that his intent was to disrupt Sunni resettlement in Hurriyah in order to maintain extortion of real estate rental income to support his nefarious activities," Stover said in an e-mail.
A senior Iraqi security official told The Associated Press the investigation into the bombing was under way and that the Iraqis were not yet convinced al-Fawadi was behind the attack, the deadliest in the capital since March.
He said al-Fawadi had broken with the Mahdi Army militia led by anti-American cleric Muqtada al-Sadr, and has been running criminal operations including extortion in Hurriyah ever since. The official spoke on condition of anonymity because he was not authorized to talk to media.
"He's a key criminal that we've been chasing for some time," said Maj. Gen. Jeff Hammond, commander of U.S. forces in Baghdad. "We believe that he's been frustrated with the significant progress that we've made" including "the willingness of tribal leaders to move on from the attacks."
Hammond said the attack was "an effort on his behalf to try to gain some authority back."
U.S. officials have long feared that a sustained bombing campaign might re-ignite sectarian warfare, and some Hurriyah residents were skeptical about claims that a fellow Shiite was responsible.
"When I went to buy bread in the morning, I heard people talking," said Hurriyah resident Ayad Hussein. "Some were blaming al-Qaida. Others were blaming the Americans. It could be done by a man who has authority and could pass all these checkpoints."
Jaafar Ali, 33, a government employee from Hurriyah, suspected Sunnis in a nearby neighborhood were to blame.
"Such things always happen for political reasons," he said. "The police and army checkpoints are to blame. They have a presence there but they do not search. They have no role whatsoever."
The attack occurred about 5:45 p.m. near a bus stop and market that was packed with shoppers buying food for their evening meal. The victims included women and children, police said.
Attacks designed to produce large numbers of Shiite civilian casualties were the hallmark of al-Qaida in Iraq, a Sunni extremist group. But Stover said the type of vehicle and explosives used in the attack were not the kind al-Qaida generally employs.
Hammond said there was no recent history of al-Qaida attacks in Hurriyah, which is overwhelmingly Shiite since thousands of Sunnis were driven from the community in the sectarian slaughter of 2006.
Last November, the U.S. military accused a Shiite splinter group for a bombing attack in a pet market in a mostly Shiite area, saying the assailants used techniques associated with al-Qaida to make Shiites think they needed militias for protection.
For years, the U.S. military has described al-Qaida as the principle enemy in Iraq, where numerous Sunni and Shiite armed groups have thrived since the collapse of Saddam Hussein's regime in 2003.
However, al-Qaida's forces have been weakened because of U.S. military pressure and the revolt against the terror movement by Sunni Arab tribes that had provided them with shelter and recruits for years.
In April, Gen. David Petraeus, the top U.S. commander in Iraq, told Congress that the "greatest long-term threat" to Iraq now comes from the "special groups," a loose network of Shiite gangs that the Americans believe receive money and training from Iran _ a charge the Iranians deny.
It was unclear whether al-Fawadi's group receives Iranian support, and U.S. officials made no mention of an Iranian connection to Tuesday's bombing.
Iraqi forces are due to start a security operation Thursday against Shiite militants in Amarah, a southern city believed to be the hub of networks smuggling weapons from Iran.
Also Wednesday, a car bomb exploded in the northern city of Mosul, wounding 14 people, the U.S. military said. Mosul is the scene of an ongoing operation against al-Qaida and other Sunni militant groups.
Associated Press writers Bushra Juhi and Qassim Abdul-Zahra contributed to this report.