Des Plaines police say three men, one of whom was holding a handgun, approached three people in separate incidents between 2:21 a.m. and 2:29 a.m.
The suspects demanded each of the victims turn over their wallets and cellphones, police said.
The suspects were last seen fleeing in a vehicle that was traveling southbound on Des Plaines River Road, according to police.
The victims described the suspects as Black males with thin builds wearing dark-colored sweatshirts and pants. The suspect holding the handgun was said to have short hair and was disguising his face with a dark-colored bandana.
Des Plaines Police detectives are investigating.