The death toll from a car bombing south of Baghdad claimed by Islamic State rose to 73 on Friday, including about 40 Iranian pilgrims.
Iraqi police and hospital officials said 65 other people were wounded in the Thursday night attack at a gas station on a major highway near the city of Hilla, about 95 kilometres south of the Iraqi capital.
The attack appears to have targeted a bus carrying Iranian pilgrims heading home after a major Shiite religious observance in the holy city of Karbala.
Islamic State view Shiites as heretics and routinely target Iranian pilgrims who visit Iraq by the hundreds of thousands to pay homage to major Shiite shrines in Baghdad.
It was the deadliest IS attack in Iraq since July, when a car bomb killed about 300 in a commercial district in Baghdad.
IS claimed the attack in a brief statement on its Aamaq media arm, saying it was a suicide truck bomb.
"Let the vile Rafidha (Shiites) know that what awaits them in the near future, God willing, will be more painful and bitter and that the flames of the battles in Nineveh will reach them in Baghdad, Karbala and Najaf," IS said in its statement.
Meanwhile, in Mosul, where an Iraqi government campaign to retake the city began last month, fighting continued on Friday.
Iraqi special forces seized another neighbourhood, Masaref, and advancing in the densely populated Zohour district.
The offensive to capture Zohour began earlier this week, but officials say troops are facing spirited IS resistance.
