Six police officers were killed and 27 injured in a wave of attacks targeting the security forces in Baghdad and Fallujah, officials said Saturday. The incidents took place late Friday and in the early morning, according to dpa. Four police officers were killed in south-western Baghdad in gun battles with insurgents, the Aswat al-Iraq news agency reported. Ten others were wounded in the incident. In the north-west of the capital, a traffic cop was killed and two other people were injured when they came under gunfire from militants. In Fallujah, a police officer was killed and three others were injured when militants shot at the checkpoint they were staffing. A manhunt was under way to capture those behind the assault. Also in Fallujah, located some 70 kilometres to the west of Baghdad, militants blew up the houses of four policemen in the city's east, injuring 12 people.