Updated at 3:00 a.m. ET Friday:
Iraqi officials say the death toll from Thursday's bombing has risen.
According to The Associated Press:
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.
In a statement, ISIS claimed responsibility.
NPR's Alison Meuse said the attack targeted Shiite Muslims returning from an annual religious pilgrimage.
Alison told NPR's Newscast unit:
The truck bomb exploded next to a rest stop frequented by Iranian travelers. An official with Iraq's interior ministry says the explosives were concealed by the truck's cargo of vegetables. It was detonated as a group of Shiite pilgrims left a nearby restaurant. In addition to the dead, dozens of civilians were wounded and cars parked nearby were incinerated.
The attack, which happened about 70 miles south of Baghdad, targeted Shiite Muslims returning from Karbala for the religious pilgrimage of Arbaeen. Alison said the Sunni extremist group ISIS, sometimes also known as ISIL, considers Shiites heretics and typically claims such attacks.
In a statement Thursday, National Security Council spokesman Ned Price said the violence "was clearly intended to stoke sectarian tensions. The United States remains steadfast in its partnership with the Iraqi people and government, and this attack only serves to strengthen our resolve in defeating ISIL."