Insurgents have launched multiple attacks on Iraqi police posts in Sunni Muslim strongholds north of Baghdad, reportedly killing at least 32 people.
In one of the apparently co-ordinated strikes, a police station south of Tikrit, was stormed by gunmen who killed 12 officers.
US forces said there were at least four other deadly ambushes around Tikrit.
Six Iraqi national guardsmen were killed in a suicide car bomb attack in Baquba, northeast of Baghdad.
Iraq's new security force is frequently targeted by insurgents opposed to the American presence in the country.
