A top Iraqi army officer said he survived a bombing on Saturday that killed nine soldiers during an operation against Al-Qaeda militants north of Baghdad, while 15 people died in other attacks.

Iraq is witnessing its deadliest violence since 2008, when it was emerging from a prolonged and bloody sectarian conflict between Sunni and Shiite Muslims.

Staff Lieutenant General Abdulamir al-Zaidi said he and other soldiers from his convoy were on foot when the bomb exploded in an area about 30 kilometres (18 miles) north of the city of Baquba.

"I was targeted directly," Zaidi told AFP by telephone, adding that he was about 50 metres (yards) away from where the bomb detonated but was unharmed.

"This area is a stronghold for Al-Qaeda," Zaidi said.

The attack took place during an operation begun on July 28 in Diyala, Salaheddin and Kirkuk provinces that aims to track down militants behind bombings and assassinations during the Muslim holy month of Ramadan.

All three provinces have been hit by frequent attacks in recent weeks, including Baquba and surrounding areas, and the search operation is still going on.

Other attacks on Saturday killed 15 more people, including multiple members of three families, officials said.

In another attack near Baquba, gunmen shot dead a woman and her two adult daughters at their home.

A Sahwa anti-Al-Qaeda militiaman said the women may have been informants for the security forces.

Gunmen also killed two brothers who were former Sahwa members and another person in two attacks near Baquba, while a bomb in the city killed one person and wounded five.

Sunni militants consider Sahwa militiamen, who joined forces with the United States from late 2006, helping to turn the tide of the war, to be traitors and frequently attack them.

In Tikrit, also north of Baghdad, a roadside bomb killed a man and his 11-year-old son as they walked in the city centre.

Gunmen also killed a judge's two bodyguards in the northern province of Nineveh, and militants attacked a police checkpoint with automatic weapons, killing a policeman.

The judge was not with the guards when they were killed.

And a bomb exploded near a market in Baghdad, while another struck a main road, killing a total of three people and wounding 10.

Militants frequently plant bombs in public areas in an attempt to sow fear and reduce confidence in the government.

Security forces are also regularly targeted.

Violence has increased markedly this year, especially since an April 23 security operation at a Sunni anti-government protest site that sparked clashes in which dozens died.

Protests erupted in Sunni-majority areas in late 2012, amid widespread discontent among Sunnis who accuse the Shiite-led government of marginalising and targeting their community.

Experts say Sunni anger is the main cause of the spike in violence this year.