Insurgents killed four people, including a man and his son, in two attacks in Diyala province in central Iraq on Wednesday, police and medical officials said.

"Insurgents raided the house of a man working in the identity card directorate ... and assassinated him and his 18-year-old son," on the outskirts of Baquba, capital of Diyala, a police officer said on condition of anonymity.

The attackers then planted a bomb near his home, with the ensuing blast killing two people and wounding five others, the officer added.

Baquba hospital received the bodies of four and treated five wounded people, doctor Ahmed Alwan said.

Diyala is a majority Sunni province but with a substantial Shiite population. It was a stronghold of Al-Qaeda during the peak of sectarian violence in Iraq in 2006 and 2007.

Although unrest has declined in the province and nationwide since that time, it remains one of the country's most dangerous regions.

A total of 126 Iraqis were killed in nationwide violence in April, according to official figures.