CHICAGO (CBS) – Chicago police are warning restaurants and other businesses of a string of robberies in the Loop and University Village over the past several days.

In each incident, a lone male suspect armed with a handgun enters the business, approaches a restaurant employee, and announces a robbery, according to a Chicago police alert.

After receiving money from the cash register, the subject flees each location on foot.

The robberies happened at the following locations and times:

• 500 block of West Roosevelt Road on August 19 at 3:50 a.m.
• 500 block of West Roosevelt Road on August 20 at 3:08 a.m.
• 300 block of South State Street on August 20 at 10:25 a.m.

Police released an image of the suspect.

Police also advised residents of what they can do to protect themselves:

• Be aware of this crime and alert nearby businesses.
• Pay attention to any suspicious persons loitering in the area.
• Have and maintain a working surveillance system.
• If video surveillance is available, save a copy of incident for Detectives.
• Call 911 immediately and provide a detailed description of any suspicious persons, including any vehicle description and license plate information.

Anyone with information is asked to contact the Bureau of Detectives Area 3 at 312-744-8263.