Five car bombs have exploded in predominantly Shia cities and districts in central and southern Iraq, killing 26 civilians and wounding dozens.

No group has claimed responsibility for the attacks, which came during a spell of sectarian violence.

Two car bombs went off simultaneously in the city of Amarah near a gathering of construction workers and a market, killing 13 people and wounding 42, according to police.

Another police officer said a car bomb exploded near a restaurant in the city of Diwaniyah, killing eight and wounding 25 others.

Amarah, which is 320km southeast of Baghdad, and Diwaniyah, which is 30km south of the capital, are heavily Shia and normally comparatively peaceful.

Hours later, another car bomb went off in the Shia city of Karbala, killing two people and wounding 12 others.

A car bomb in a Shia neighbourhood in the otherwise predominantly Sunni town of Mahmoudiya, about 30km south of Baghdad, killed three and wounded 16.