BAGHDAD — Iraqi officials say gunmen have killed at least four people and wounded three in attacks in the northern city of Mosul.

Police say gunmen fired at a police checkpoint in the center of the city early Sunday, killing two policemen. Later in the day, gunmen killed an off-duty soldier at a car repair shop in Mosul.

Police say that in a third attack, gunmen fired at a van carrying oil workers, killing one and wounding three.

A health official confirmed the casualty figures. The health official and two police officers spoke anonymously because they were not authorized to release the information.

Violence has dropped in Iraq since the country's worst sectarian fighting in 2006-2007, but insurgents carry out near-daily attacks on security forces and civilians to try to undermine the Shiite-led government.