Officials said the incident happened at a Wendy's in a strip mall at 87th and Lafayette, right off the Dan Ryan Expressway.
Chicago police said at about 3 p.m., a 38-year-old male armored truck guard left a business at the strip mall. As he approached the truck, a gold or dark gray vehicle approached. Three individuals exited the vehicle and opened fire on the guard, hitting him in his bulletproof vest, the FBI said.
The Chicago Fire Department said one of them was struck and his partner took him to Roseland Hospital with a graze wound to the belly. He is expected to make a full recovery. Police said he is listed in good condition.
Police said no money was taken from the truck or the guards.
A security guard at another business in the strip mall witnessed the shooting and said the car had been circling the parking lot for some time before opening fire on the armored truck guard.
No one is currently in custody. An investigation is ongoing.
Track crime and safety in your neighborhood