At least 13 police recruits have been killed in an attack on two buses near the northern Iraqi city of Baquba.
The buses, which were carrying 80 volunteers, came under attack from insurgents near the town of Muradiya, in Diyala province.
A roadside bomb killed one recruit and 12 were killed by small-arms fire. About 25 were injured, while others were abducted.
The attack comes amid a surge in violence in the country.
In other attacks:
- Six people were killed in a suicide bombing in central Baghdad
- Three people were killed in a bomb blast near a Baghdad market
- The US military announced the deaths of two more soldiers, bringing the number of US troops killed in October to 80
A police source told the BBC Baghdad bureau that US troops investigating the scene of the attack on the police recruits found that the bodies had been booby-trapped.
The volunteers had joined the police from a Shia militia, the Mehdi Army, the source said.
They were evacuating their base in Diyala after sustaining repeated mortar and rocket attacks.
Baquba, 65km (40 miles) north of Baghdad and a mixed Sunni-Shia area, has been the scene of large-scale sectarian bloodshed.
A three-day curfew has been imposed in the city, police sources told AFP news agency.
The Iraqi government and US forces see the training of an independent, effective police force as crucial to the future of the country, and as a result insurgents have often targeted recruits.
The attack came as British Defence Secretary Des Browne said he believed Iraqi forces could be capable of taking control of security in the south in a year's time.
On Saturday, US President George W Bush discussed changing tactics with top US commanders to try to combat the unrest.
A new poll suggests two-thirds of Americans believe the US is losing the war in Iraq, a proportion which analysts says could translate into a drubbing at the polls for Mr Bush's Republican Party in next month's mid-term elections.
The BBC's James Westhead in Washington says that while there is no official change in US strategy, change is on everyone's lips.