Health officials confirmed at least 50 people were killed in Southern Iraq on Thursday as a result of two separate attacks.
Yahya al-Nassiri, the area's governor, said the attack began with militants opening fire at the checkpoint and the restaurant on the main highway that links Baghdad with the southern provinces.
The so-called Islamic State group has said it carried out the attack. Before the death toll was raised dramatically, hospital officials had said that four Iranian citizens were among those killed.
That was followed by two suicide bombers, including one driving an explosives-laden auto, he said.More news: Protesters Demanding Arrest of Ryan School Management Lathicharged
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He warned that the death toll could rise as numerous wounded were in serious condition.
The area targeted is often used by Shia pilgrims and visitors from Iran on their way to the holy cities of Najaf and Karbala further north.
The half-dozen assailants, disguised as members of paramilitary units of popular mobilization (PM), composed mainly of militia and volunteers, shi'a, was travelling in military vehicles stolen. In a statement released by its propaganda arm Amaq, ISIS said several suicide bombers had staged the assault on a restaurant and a security checkpoint.
The toll makes it the deadliest Daesh attack in Iraq since pro-government forces drove the extremists out of second city Mosul in July. It occurs in aftermath of a visit of iraqi prime minister, Haider Al-Abadi, in province of Dhi Qar, in particular, to Nasiriyya.