A string of car-bombings and armed attacks - the latest on a police station in the northern city of Kirkuk - have established a pattern of insurgents targeting Iraqis seen as collaborating with the occupation authorities.
By Barbara Plett
BBC correspondent in Baghdad
The US-trained police force has been hit especially hard - Iraqi officials say at least 300 have been killed so far in attacks.
Iraqi recruits have suffered hundreds of casualties in attacks
The Iraqi resistance has not stated its aims, but it seems to be hitting at a key plank of US policy.
The Americans want to turn responsibility for security over to Iraqis by June and pull back to the safety of military bases.
Critics say the plan is to reduce the number of US casualties and end America's status as an occupier before presidential elections in November.
US officials say the attacks on police are actually a sign that the new security forces are effective, that the insurgents are feeling the pressure.
POLICE STATION ATTACKS
23 February 2004: "Many" killed in a suicide car bombing attack at Kirkuk station
14 February 2004: At least 20 killed in gun battle outside Falluja station
10 February: At least 45 die in blast in Iskandariya
31 January: Nine killed in blast outside Mosul station
14 December 2003: Car bomb in Khalidiya kills 17
22 November: At least 18 die in twin bombings in Baquba and Khan Bani Saad
They are also pushing their own evidence that al-Qaeda is plotting to foment civil war inside Iraq.
But the latest attacks seem less about sectarian tensions and more about a general strategy to destabilize the country.
That's at least partly the perception in places like Iskandariya, where most of those killed in a bombing on 10 February were civilians waiting to apply for police jobs.
The message there is that no one is safe, whether they belong to the police force or are just thinking about joining it.