47 people have been killed in an explosion in the city of Mosul.
The suicide attack happened inside a Shia mosque during a funeral procession. At least 81 people were wounded. US troops have cordoned off the area near the mosque.
Iraqi officials have accused Sunni Muslim insurgents of attacking Shia targets in order to spark a civil war in the religiously-divided country.
Meanwhile, an Iraqi police chief and two other officers were shot dead in an early morning ambush in the capital, Baghdad.
Insurgents dressed in Iraqi police uniforms set up a fake police checkpoint and stopped Lieutenant Colonel Ahmed Obeis's convoy as he was on his way to work.
They asked Lt Col Obeis his name before fatally shooting him and two of his companions. One of the insurgents filmed the attack.
The chief was in charge of the Salhiyah police station on the west side of Baghdad.