At least 64 people were killed when a bomb went off at a market in Baghdad, according to Iraqi police.
An additional 87 people were injured in the attack in the largely Shiite neighborhood of Sadr City.
Pictures of the aftermath of the explosion showed hundreds gathered near a chaotic scene. Blood marked the street, cars had their windows blown out and nearly an entire sidewalk was left charred.
ISIS has claimed responsibility for the attack in a statement on social media, saying it was targeting Shiite militias. Police said the bomb was placed in a parked car.
The Sunni terror group has claimed responsibility for a number of attacks in Iraq in recent weeks, including one last month east of Baghdad in which more than two dozen people were killed.