KIRKUK, Iraq -- A suicide bomber struck outside a bank as elderly men and women waited to cash their pension checks yesterday, killing 23 people and wounding nearly 100 in this oil-rich northern city that has become a flashpoint for sectarian tension.
Elsewhere, five Iraqi soldiers were killed and two wounded in a suicide car bombing at a checkpoint in Kan'an, 30 miles north of Baghdad, and the bodies of 24 men -- apparently victims of recent ambushes -- were brought to a hospital in the capital.
A US soldier was killed in a roadside bombing targeting a US convoy in southern Baghdad, according to the military, which also said that two soldiers assigned to a Marine unit were killed in a similar attack Monday in the western city of Ramadi.
The violence in Kirkuk was the worst to hit the ethnically mixed city, 180 miles north of Baghdad, since the war started in 2003. The largest previous attack was the Sept. 4 suicide car bombing outside an Iraqi police academy in the city that killed 20 people.
A man wearing a belt packed with explosives blew himself up outside the Rafidiyan Bank just after it opened yesterday morning, said General Sherko Shakir, Kirkuk's police chief.
A crowd of street vendors and elderly men and women waiting outside the bank bore the brunt of the blast, and a pregnant woman and several children were among the victims.
Body parts were strewn about in a 20-yard radius from the scene of the explosion, which occurred near a pedestrian bridge. Several bodies were under the wreckage and at least two parked cars nearby were set ablaze.
''It was the biggest awful crime in Kirkuk since the fall of Saddam Hussein's regime," Shakir said.
Al Qaeda's northern affiliate, the Ansar al-Sunnah Army, claimed responsibility for both suicide bombings in northern Iraq and threatened more violence in retaliation for the arrests and killings of Sunni Arabs.
The US soldier was killed on the 230th anniversary of the formation of the US Army. At least 1,704 US military members have died since the war began in 2003, according to an Associated Press count.
Also yesterday, US Marines and Iraqi soldiers killed five Iraqi civilians at an entrance to the volatile western town of Ramadi shortly after a suicide attack on a military checkpoint left one Iraqi soldier dead, the military said.
Insurgents have launched deadly attacks in Kirkuk apparently seeking to foment ethnic tension in the city populated Kurds, Sunnis, Shiites, and Turkmens.
The motives behind the Kirkuk attack were unclear, but it coincided with the swearing in of veteran guerrilla leader Massoud Barzani as the first president of Iraq's northern Kurdistan region in nearby Irbil, 50 miles north of Kirkuk.
Kurds have long coveted Kirkuk as the capital of an autonomous Kurdish region encompassing all three of their northern provinces.
Prime Minister Ibrahim al-Jaafari, speaking in parliament after the Kirkuk attack, also accused the insurgents of targeting civilians.
Jaafari's 37-member government was overwhelmingly approved on a vote of confidence in the 275-member parliament. But the government has been criticized for its inability to stop insurgent attacks.