The bloodiest incident was a brazen assault on the local council building in the northern town of Hawija. The attackers detonated three car bombs before engaging security forces in an hour-long firefight, the commander of the army's 12th Division, Brig. Gen. Mohammed Khalaf told The Associated Press by telephone.
Khalaf said at least one of the car bombs was driven by a suicide attacker. He put the death toll at seven civilians and two soldiers in addition to 21 others wounded. Four militants were killed while the rest fled, he added.
Hawija, a former insurgent stronghold, is about 240 kilometers (150 miles) north of Baghdad. It was the site of a bloody April crackdown by security forces on a Sunni protest camp that set off the current surge of violence, in which over 4,000 people have died.
The attack came a day after security forces foiled an attempt by insurgents to take over a Sunni town near the Syrian border. Eleven people were killed there, including six attackers.
Earlier in the day in Baghdad's northern Shaab neighborhood, gunmen armed with weapons fitted with silencers broke into the house of an Interior Ministry employee, killing him, his wife, mother-in-law and three children, a police officer said. The children were aged three, six and eight years old, he added.
Police said they did not know the motive behind the killings, but insurgents often target government officials and their families in a bid to undermine confidence in the government.
In another attack, gunmen ambushed off-duty soldiers traveling through the town of Taji, about 20 kilometers (12 miles) north of the Iraqi capital, opening fire on their car and killing two, another police officer said. Three others were wounded, he added.
At night, a bomb exploded near a market in the northern city of Mosul, killing three people and wounding 23 others, said police.
And in Baghdad, a car bomb blast on a commercial street in a western district killed five and wounded others, police said.
Medical officials confirmed the casualty figures for all attacks. All officials spoke on condition of anonymity as they were not authorized to release information.
No one has claimed responsibility for the attacks, but they bear the hallmarks of al-Qaida's local branch in Iraq, known as the Islamic State of Iraq.
Al-Qaida is believed to be trying to build on Sunni discontent toward what they consider to be second-class treatment by the Shiite-led government.
Associated Press writer Sinan Salaheddin and Sameer N. Yacoub contributed.