Bombings mainly targeting Shiite areas of Baghdad and attacks on security force checkpoints in and around the capital killed at least 21 people Wednesday, officials said.
Iraq has been hit by a year-long surge in bloodshed that has reached levels not seen since 2008, driven by widespread discontent among its Sunni Arab minority and the bloody civil war in neighbouring Syria.
And Baghdad is hit by near-daily bombings and shootings.
Wednesday's seven car bombs and two roadside bombs, which struck six different areas of Baghdad, killed at least 14 people and wounded more than 70 people, the officials said.
One of the car bombs exploded near the University of Technology in the Karrada district of central Baghdad, killing three people and wounding at least 10.
"The terrorist was planning to blow up the car on the main road near the university," but security forces do not allow cars to stop there so he instead left it on a side street, a police officer at the scene said.
An AFP journalist saw the charred remains of the car, and said two cars and several nearby homes were damaged by the blast.
While there was no immediate claim of responsibility for the attacks, Sunni jihadists often target members of Iraq's Shiite Muslim majority, whom they consider to be apostates.
Gunmen later attacked three checkpoints in Baghdad while a roadside bomb exploded near a fourth in Tarmiyah, north of the capital, killing at least four police and three soldiers.
Gunmen also attacked a bus northeast of the city of Baquba, killing an Indian man and wounding four others.
The violence came a day after two suicide bombers attacked the city council headquarters in Samarra, north of Baghdad, and took employees hostage.
A third bomber detonated an explosives-rigged vehicle after police and anti-Al-Qaeda militiamen arrived at the scene, while the two inside blew themselves up after exchanging fire with security forces.
- Militants strike with impunity -
The violence, which showcased the impunity with which militants can strike even targets that should be highly secure, killed six people and wounded 46.
Powerful militant group the Islamic State of Iraq and the Levant (ISIL), which operates in both Iraq and Syria, claimed the attack in a statement posted on the Honein jihadist forum.
The statement said that "three lions of the Islamic State" attacked the building, "killed its guards and executed its members, and took complete control of the council."
Militants have carried out similar assaults elsewhere in Salaheddin province, north of Baghdad, and battled security forces for control of the Sulaiman Bek area, killing dozens of people.
The government also faces a more than two-month crisis in Anbar province, west of Baghdad, where it has lost the city of Fallujah as well as shifting parts of provincial capital Ramadi to anti-government militants.
This is the first time anti-government forces have exercised such open control in major cities since the peak of the deadly violence that followed the US-led invasion of 2003.
More than 370,000 people may have been displaced by the violence in Anbar during the latest crisis, according to the United Nations.
Violence in Iraq has killed more than 1,800 people since January 1, according to AFP figures based on security and medical sources.