Scores of people were killed and injured when a car bomb exploded at a police station in Khalidiyah, about 60km west of Baghdad, on Sunday, according to reports.
The BBC said at least 16 were killed and 20 injured; CNN, however, quoted witnesses as saying that 18 were killed and 28 injured.
Sixteen of those killed were policemen and two were civilians, CNN quoted witnesses as saying. Of the 28 injured, more than 15 were police officers, the witnesses said.
No coalition forces were killed or hurt.
Khalidiyah is located in the so-called Sunni triangle north and west of Baghdad, which is known to be a stronghold of supporters of the ousted Iraqi President Saddam Hussein.