Chicago police conducted an active shooter drill at Water Tower Place, according to a news report

The drill began at 6 a.m. at the Loop shopping center, located along Chicago's Magnificent Mile, and ended around 8 a.m.

The drill, says the report, is designed to help train the Chicago Police Department and Water Tower Place security in the case of an active shooter situation. Forty to 50 people participated in the exercise, simulating a person opening fire inside the mall. Training activities took place both in and outside of the Water Tower, notes the report.

Brian Hopkins, a Democratic Alderman of Chicago, representing the 2nd ward, said these emergency drills are usually discreetly performed in the early morning hours, but a decision was made to alert the public after an incident occurred earlier this summer during a drill that the public was not made aware of. During the drill, signage was posted on streets to avoid any confusion or panic from residents in the surrounding areas, adds the report.