At least 20 people have been killed in a string of car bombings across Iraq.

On Sunday, seven vehicles rigged with explosives went off in five cities south of the capital Baghdad during morning rush hour, leaving 56 other people wounded in mostly Shia areas of Iraq.

Car bombs went off in Kut, Aziziyah, Mahmudiyah, Nasiriyah and Basra, officials said.

In Kut, provincial capital of Wasit and 160 kilometres(100 miles) south of Baghdad, a car bomb exploded outside a restaurant in an industrial area packed with vehicle repair garages, killing seven people and wounding 15.

Another car bomb in nearby Aziziyah in the town ' s main marketplace and near a Shiite mosque killed five and wounded 10.

Twin blasts in the southern port city of Basra, meanwhile, killed five people, including a bomb disposal expert looking to defuse one of the rigged vehicles.

Three others were killed in bombings in Nasiriyah and Mahmudiyah.

The violence was the latest in a spike in attacks nationwide, with last month registering the highest death toll since 2008.