Gunmen opened fire at a minibus carrying workers to a US military base northeast of Baghdad on Wednesday, killing nine of them and wounding a tenth, a police source said.

"Unknown armed men opened fire from their car at a minibus carrying Iraqis workers of a US military base at about 7:15 a.m. ( 0415 GMT) near the area of Abu Saida, some 15 km northeast of Baquba," the source at the joint US and Iraqi coordination office in Baquba told Xinhua on condition of anonymity.

Nine workers were killed, including three brothers, and a tenth was wounded in the drive-by shooting, the source added.

Baquba, some 65 km northeast of Baghdad, has witnessed violent insurgent attacks in the past.

Insurgents frequently target Iraqis working for the US military, accusing them of being collaborators with the occupation forces.

Source: Xinhua