Attacks killed five Iraqis, including three who died when a suicide bomber blew up an explosives-packed truck in the northern city of Kirkuk, and an American soldier on Thursday, officials said.
In the deadliest attack, blamed on Al-Qaeda, two women and a man were killed and 76 others were wounded by a truck bomb in front of a bank in Kirkuk as policemen collected their monthly salaries.
The hurt included 26 policemen, more than 20 employees of the targeted bank as well as surrounding offices, and the rest were civilians, according to Kirkuk provincial health director Sadiq Omar Rasul.
"Al-Qaeda is trying to send a message that they are there," said provincial police chief Major General Jamal Taher Bakr. "They are trying to ignite sectarianism between Kirkuk's communities."
An AFP correspondent at the scene said the blast caused massive damage to the bank and surrounding buildings. Several police vehicles were ablaze, and access to the bank was blocked.
Parliament speaker Osama al-Nujaifi said provincial security forces were responsible for a "dangerous violation of security," and called for a full investigation into the attack.
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Iraq's northern Kurdish region wants to incorporate Kirkuk province, which is ethnically mixed and rich in energy, into its autonomous three provinces, a move strongly opposed by the authorities in Baghdad.
In northern Iraq, an American soldier was killed, the first such death in the country in more than two months.
"A US service member was killed Thursday in northern Iraq," a brief US army statement said. It gave no further details.
The last US soldier to be killed in Iraq died on July 15 in the southern province of Basra, according to independent website www.icasualties.org. Three American soldiers have died since then, but all in "non-hostile" incidents.
Thursday's death brings to 4,477 the number of American soldiers to have died in Iraq since the 2003 US-led invasion of the country, according to an AFP tally based on data compiled by icasualties.org.
An Iraqi policeman was also gunned down in Baghdad on Thursday, while a soldier was killed and two others wounded by a mortar attack against an Iraqi military base in Tarmiyah, just north of the capital, according to police and an interior ministry official.
Violence is down nationwide since its peak in 2006 and 2007, but attacks remain common. A total of 239 people were killed in violence in Iraq in August, according to official figures.