CHICAGO (CBS) — Police are warning Southwest Side store owners and clerks about a string of recent armed robberies.

In each incident, the robber walked into a store and demanded property from the cash register at gunpoint, according to an alert from Chicago Police.

The first robbery happened at 9:35 p.m. July 3 in the 4400 block of South Archer Avenue, while the other incident happened at 9:22 p.m. July 16 in the 7000 block of South Pulaski Avenue, police said.

The robber was described as a black man with a medium-to-dark complexion, standing between 6-feet and 6-foot-3 and weighing between 200 and 250 pounds, police said.

Anyone with information should call Area Central detectives at (312) 747-8382.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2017. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)