(KUNA) -- Six people were killed and seven others were injured when a suicidal bomber wearing an explosive belt blew himself up in the city of Ba'aquba west of the Iraqi capital Tuesday, security sources said. The sources that requested anonymity said a suicidal bomber blew himself in the back entrance to the building of the police command of Diyala, located in the heart of Ba'aquba. The attack killed six poeple including three police officers and two women, while seven others were seriously injured, including three police personnel, the sources added.This is the seventh suicidal attack in Ba'aquba -- witnessed in four months.