Skokie police said officers responded to a report of a person with a gun in the area just after 2:30 p.m.
Just after 3 p.m., Skokie police posted on X, saying there was activity around the mall and asking the public to avoid the area.
Chopper 7 was over a large police presence outside the mall's Nordstrom store around 3:20 p.m.
Skokie police ask public to avoid area of Old Orchard Mall
Shoppers and employees inside the mall were forced to shelter behind locked doors until police gave the all-clear.
"I was just walking into the store when the door immediately got locked, and we were urged to go to the back," said shopper Jose Morales. "Once we were back there, they put the door on lock and there was a device to, like, make sure that the door can't open. So you got that sense, like, I'm in a safe spot, but then you started thinking, I want to leave. And they're like, 'Oh, we can't let you go due to the threat.'"
A preliminary investigation revealed that dispute between two people caused the incident, police said. Those two people were detained as part of the investigation.
A mall official told ABC7 the lockdown lasted about an hour, adding that no injuries were reported.
"There was a lot of people around me, like, crying," Morales said. "I know a similar situation happened at Oak Brook, and seeing how they reacted to that, it could've been here, it makes you think every day. But really, these procedures in place really just helped everyone keep safe."
Skokie police said no shots were fired. Police and a mall official said visitors can now resume normal activity at the mall.
Around 3:40 p.m., officers were seen surrounding the nearby Old Orchard Towers office building, located at 5202 Old Orchard Road.
It was not immediately clear if that police activity was related to what happened at the mall.
Macy's issued a statement, saying, "The safety of our customers and colleagues is always our top priority. To provide a secure and pleasant shopping environment, we have Asset Protection staff in our stores and cooperate with mall security and law enforcement agencies to address any potential risks."
Skokie police are investigating and asked anyone with information to contact them at 847-982- 5900.
Authorities did not immediately provide further information.