Iraqi officials say four people have been killed in two separate attacks in Iraq.
Police and hospital officials say two policemen died in Saddam Hussein's hometown of Tikrit when gunmen in a speeding car opened fire at a checkpoint early Friday.
Two policemen were wounded in the attack in Tikrit, 80 miles (130 kilometres) north of Baghdad.
Police and hospital officials say a roadside bomb struck a civilian bus in the southern part of Baghdad on Friday morning, killing two people and wounding seven.
All officials spoke on condition of anonymity because they were not authorised to talk to the media.
Violence in Iraq has subsided significantly but militants often target security forces to destabilise the country.