At least 13 people were killed in clashes between police and insurgents in Baghdad on Monday, said a medical source at Yarmuk hospital.
Nine of the dead were police while the rest were passers-by, said the source, who added that 20 policemen were also wounded.
The clashes took place in the western neighbourhood of Yarmuk and the southern areas of Saidiyah and Dura.
Monday was the first day that traffic moved freely in Baghdad with the lifting of a three-day curfew in the wake of a series of bomb attacks on the Shiite slum of Sadr City on Thursday that killed over 200 people.
Despite the curfew, dozens more people have been killed since then in revenge attacks.