The Chicago Police Department's Hostage Barricade Terrorist Incident Unit was called to the intersection of West 35th Street and South Artesian Avenue following an incident at 3:11 a.m., according to police News Affairs Officer Ronald Gaines.
Police surrounded a building near the intersection while they searched for a gunman whom authorities said could have been wearing body armour.
As of 10:55 a.m., police terminated the search for a suspect and there were no arrests, police News Affairs Officer Laura Kubiak said.
Details about the nature of the incident were not immediately available.
(The Sun-Times Media Wire contributed to this report.)