Suicide bombers attacked a restaurant and a police checkpoint near the southern Iraqi city of Nasiriyah on Thursday, leaving scores dead and many more injured.

Local officials said the death toll was likely to climb with many of the wounded in a serious condition.

The attack started when unidentified gunmen opened fire at people in a highway restaurant. One attacker detonated his explosive vest inside the restaurant.

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The remaining attackers then got into a car and drove to a nearby security checkpoint, where they blew themselves up.

The militants were disguised as members of the Hashed al-Shaabi, a mainly Shiite paramilitary force that has fought alongside the army against the so-called Islamic State militants in northern Iraq, AFP news agency reported, citing security sources.

Iranian pilgrims among dead

IS claimed responsibility for the attacks in a statement on its Amaq news agency, where the Sunni Muslim militant group said it had killed "dozens of Shiites."

Hospital sources told Reuters news agency that at least 10 Iranian pilgrims, who were visiting holy Shi'ite shrines, were among the dead.

IS-backed attacks in southern Iraq, where the bulk of the country's oil is produced, are relatively rare thanks to a tighter grip maintained by the Iraqi security forces.

The area targeted on Thursday is on a highway used by Shia pilgrims and visitors from neighboring Iran to travel to the holy cities of Najaf and Karbala further north.

ap/sms (Reuters, AFP, dpa)