Four policemen were wounded when a mortar round struck a police checkpoint in eastern Baghdad on Wednesday, a well-informed police source said.

"A mortar round landed close to a police checkpoint in the Palestine Street area, wounding four policemen," the source told Xinhua on condition of anonymity.

Meanwhile, a suicide truck bomber struck a police checkpoint at the entrance of the Doura refinery in southern Baghdad, killing three people and wounding 13 others.

Violence has persisted in Iraq as bombings and assassinations cause dozens of casualties daily.

Source: Xinhua