Car bombs exploded near a police station near Iraqi city of Kirkuk, killing three policemen and wounding seven, as militants opposed to Sunday's elections continued their campaign of violence across the country.
Another policeman was killed when gunmen opened fire on the local headquarters of three political parties in the city of Baqouba, north of Baghdad.
The buildings house the city's offices of the Communist Party, the Patriotic Union of Kurdistan and the United Iraqi Gathering. Four bystanders were injured in the attacks.
Later, at least two car bombs exploded in Riyadh, town southwest of Kirkuk. Police said one blast was near the town's police station and the other close to the central market area.
About 10 minutes after the blasts, a US combat patrol heading to the scene came under small arms fire and two US soldiers were slightly wounded.
Riyadh is near the town of Hawija, a Sunni Arab settlement that has seen frequent unrest over the past year. Sunni insurgents have repeatedly targeted Iraqi police and soldiers ahead of the elections, accusing them of collaborating with US-led occupiers.
Government officials, election workers and Shi'ite clerics have also been killed in the run-up to the ballot, Iraq 's first since the fall of Saddam Hussein in April 2003.
Elsewhere, a car bomb targeting a US convoy exploded on the road to Baghdad's international airport today.
The US military and Iraqi police had no immediate information on casualties.