More than 40 people were hurt in the attacks in Samarra.
Iraqi officials and police are often targeted by rebels who don't like the fact they are working with the US, who they think should leave the country.
On Friday night, locals were told to leave Falluja to prepare for strikes by US planes.
Meanwhile, Kofi Annan, the head of the United Nations, has asked US and Iraqi leaders to think again before attacking the area.
He's worried the attack could make the situation there worse, by angering local Iraqis.