It happened in the Roseland area near 95th Street and LaSalle at approximately 5 p.m. Sunday.
Officers say they pulled over the car full of young people for speeding and that the driver got out, and a passenger then suddenly put the vehicle in reverse.
That's when police opened fire.
An officer reports that one of the passengers was hit when the car backed up and that he was being dragged away when the car started to pull off. It was not clear how the other person was injured.
Some type of weapon was recovered from the scene.
Two teenagers were in serious but stable condition Monday.