Police responded to a call of a robbery at 8:33 p.m. in the 11300 block of South Pulaski Road in Mount Greenwood, a Chicago Police Department spokeswoman said.
The four victims included three boys and one girl — all either 15 or 16 years old.
They told police three robbers, ages 16-18, walked up to them, and one pointed a gun at them. The other two robbers beat them before running off with the victims' property, police said.
The victims were injured but refused medical attention on the scene, police said.