Bombings and shootings killed more than 32 people across Iraq on Sunday, underscoring the government's struggle with a stubborn insurgency more than nine months after the last US troops withdrew.

In Taji, 20 km north of the capital Baghdad, bombs in three parked cars went off separately, killing 11 people and wounding 24, including several policemen.

Reuters footage of the scene of one of the explosions showed the remains of an exploded car surrounded by several completely and partially destroyed houses and cars.

Taji has one of Iraq's largest military airbases but the bombing hit a civilian neighbourhood.

"A car bomb entered the area and no one... noticed this. Why did that happen? All the houses were destroyed," said Khadiar Abas, owner of one of the damaged homes.

In Baghdad, a suicide car bomb and two parked car bombs went off, killing eight people including a police officer and wounding another 11.

Another blast targeted a bus carrying Iranian pilgrims as it passed through the town of Madaen, about 30 km southeast of Baghdad, killing two passers-by and wounding another ten, including seven Iranians.-Reuters