CHICAGO (CBS) — With both the nation, and the city, on high alert, police are taking no chances on potential terrorist threats.

Last night, there was a large police response on the Gold Coast, as officers were trying to figure out whether an incident was the real deal, a false alarm or a drunken joy ride.

On Rush Street last night, SWAT teams descended with heavy weapons, after two people pulled up in a white van and yelled out that they were with ISIS.

The suspects were described as bearded men in a white van with temporary plates. When police tried to stop them, the van sped away.

Uniformed cops and SWAT teams buzzed the area but they never caught the suspects.

Police now believe they were probably just joking around.

CBS 2 Security Consultant Ross Rice said: “It’s something common sense would tell you you can’t and shouldn’t do.

“You can’t make false threats. You can’t claim there’s a bomb on a plane. You can’t go up and down the street yelling you’re ISIS. It just doesn’t work.”

Today, SWAT teams hit the CTA Blue Line at LaSalle after reports of a suspicious person of “Middle Eastern descent who kept looking around suspiciously,” according to police dispatch reports.

Despite the response, police later said the report was unfounded.