Gunmen attacked an Iraqi security checkpoint in southern Baghdad on Thursday, killing four policemen and wounding six others, a police source told Xinhua.

"Armed men opened fire at about 7:10 a.m. (0410 GMT) at a police checkpoint erected under a bridge in Doura district," Captain Ahmed Abdullah from Baghdad police said.

"Four policemen were killed in the attack and six others were wounded," he added.

According to the source, the policemen were sleeping when the gunmen surprised them.

Insurgents frequently attack Iraqi government employees and security forces, accusing them of collaboration with the US occupation forces.

Source: Xinhua