In the first attack, a suicide bomber detonated his vest and gunmen opened fire inside a roadside restaurant near Nasiriya, the capital of Dhiqar province, security sources said.

Soon afterwards, a car bomb exploded at a nearby checkpoint. One report said four Iranians were among those killed.

The so-called Islamic State group has said it carried out the attacks.

According to news agency AFP, one report said the attackers were disguised as members of Hashd al-Shaabi (Popular Mobilisation) - a mainly Shia group that has fought alongside Iraqi forces against IS.

IS are enduring defeat after defeat on front lines in both Iraq and Syria, but they remain capable of launching devastating assaults on soft targets, says BBC Middle East editor Alan Johnston.

The area targeted is frequented by Shia pilgrims and visitors from Iran on their way to the holy cities of Najaf and Karbala to the north.