Iraqi police say bombings in several parts of the country have killed at least one police officer and wounded several others.

In the northern city of Mosul, a bomb attached to a police car killed a policeman and wounded four others.

In Baghdad, two separate bomb attacks wounded at least four people.

And a fourth bomb attack wounded two people in the town of Tuz Khurmatu, some 175 kilometers north of Baghdad.

Violence has decreased in Iraq since its peak in 2006 and 2007, but attacks remain common.

U.S. and Iraqi officials have expressed concern about Iraq's ability to handle security after U.S. forces withdraw at the end of the year.