Baghdad: Bomb and gun attacks in Iraq have killed eight people, including four anti-Al Qaida militiamen, and wounded 12 others, security officials said on Friday.

"Four people were killed and seven wounded in two attacks by roadside bombs in the Taji area," just north of Baghdad, an interior ministry official said.

The first attack targeted the home of Nadhem Karim Mohammad, a leader of anti-Al Qaida Sahwa militia forces in Taji, killing him and his mother about 7am (0400 GMT), the official said.

When police arrived at the scene, another bomb went off, killing two police and wounding seven others. Unknown gunmen attacked a Sahwa checkpoint in the Al-Sharqat area, 120km northeast of Tikrit, killing three Sahwa members and wounding two others, a police major said.

And in Al Tuz, about 75km south of the northern oil city of Kirkuk, a magnetic "sticky bomb" on a car killed a policeman while a roadside bomb wounded three civilians, police Major Khalid Al Bayati said.

A security source also said that police had freed Ibrahim Zaki Khalaf Al Ajili, the teenage son of a well-known contractor in Tikrit, who was kidnapped on Thursday.

Ajili was freed about 110km south of Kirkuk, the source said, adding that two suspected kidnappers believed to belong to the Ansar Al Sunna insurgent group were detained. Violence has declined in Iraq since its peak in 2006 and 2007, but attacks remain common.

A total of 187 people were killed in November, according to official figures released on Thursday.