Iraqi hospital and police officials say the death toll from a car bombing south of Baghdad claimed by the Islamic State group has risen to 73, including about 40 Iranian pilgrims.

The officials said Friday that 65 people were wounded in the attack. Earlier, they had put the death toll from the Thursday night bombing at 56.

The attack took place at a gas station on a major highway near the city of Hilla. The officials spoke on condition of anonymity because they were not authorized to talk to the media.

IS claimed the attack in a statement, saying it was a suicide truck bomb.

The bombing appears to have targeted a bus with Iranian pilgrims heading home after a major Shiite religious observance in the holy city of Karbala.