No group immediately claimed responsibility for the attacks in eight towns and cities that also wounded more than 40, but militants such as Al-Qaeda's front group in Iraq regularly target officials in a bid to destabilise the government.

They also regularly attack pilgrims.

The violence comes after anti-government protesters blocked a key highway to Syria and Jordan, amid political tensions between Prime Minister Nuri al-Maliki and a secular Sunni-backed party in his fragile national unity government.

In the deadliest attack, seven people -- three women, two children and two men -- were killed when three houses were blown up in the town of Mussayib south of Baghdad, a local police officer and a medic said.

Four others were wounded.