Twin roadside bomb blasts in east Baghdad killed five policemen and wounded seven other people, an Iraqi interior ministry official said.
The explosions targeted a police patrol in the Ghadeer neighbourhood, the official said, on condition of anonymity. Of the seven injured, three were police and the others civilians.
The violence comes after al-Qaida's front group in Iraq threatened a campaign of 100 attacks, starting mid-August, to avenge the death of Osama bin Laden in a US special forces raid in Pakistan on May 4.
Violence is down across Iraq from its peak in 2006 and 2007, but attacks remain common.
A total of 259 people were killed in violence in Iraq in July, according to official figures, the second-highest figure in 2011.