Dozens killed in double car-bomb attack in southern Iraq

"The hospitals have received 33 dead," a senior official in the Muthanna health department, which covers Samawa, told AFP.

An officer in Muthanna Operations Command confirmed the toll.

They said at least 50 people were also wounded in the blasts in Samawa, 230 kilometres south of Baghdad.

"Two car bombs went off in the town. The first one was at around midday near a bus station in the city centre," a senior police officer in Muthanna province said.

"The other exploded about five minutes later, 400 metres from the spot of the first explosion," he said.

The ultra radical jihadist group Islamic State later claimed responsibility for the attacks.

Samawa is the capital of Muthanna and lies deep in Iraq's Shia heartland and such attacks there are rare.

Muthanna also borders Saudi Arabia and a vast Iraqi desert that connects the troubled province of Anbar with the south.

A car bomb just outside Baghdad on Saturday killed at least 23 people, according to security and medical sources.

That attack targeted Shia faithful walking to the northern Baghdad shrine of Imam Musa Kadhim, the seventh of 12 imams revered in Shia Islam.

The Iraqi capital remains on high security alert for a whole week as the faithful walk from all over the country to commemorate Imam Kadhim.

IS, which considers Shias heretics, almost systematically attempts to target pilgrims marching to holy sites during Iraq's many religious commemorations.