“Around 10 pm (1900 GMT), a car bomb blew up in the garage of the home of a police captain,” said a police officer in Salaheddin province.
“While the police captain had gone out with one of his sons, a terrorist parked the booby-trapped vehicle in the garage, the door of which had been left open.
“Four of his children and his wife were killed, and four neighbours wounded,” the officer said, adding that all the children were less than 10 years old.
A hospital official in the provincial capital Tikrit confirmed receiving the bodies of the dead.
The bombing struck in Ad-Dawr, just outside Tikrit, where US forces captured now executed dictator Saddam Hussein in December 2003.
It came as Al-Qaeda front group the Islamic State of Iraq claimed responsibility for Monday’s wave of 29 separate attacks in 19 cities, which shattered the relative calm that had held in the lead-up to the Muslim fasting month of Ramadan.