Police say some 500 teenagers converged on Millenium Park, the Mag Mile and surrounding areas Wednesday night where they trespassed and caused disturbances.
Chicago police Chief of Patrol Fred Waller told reporters what the cops were dealing with while trying to corral the large crowds.
"We do have an element that starts a lot of lawlessness, running around, doing things that they shouldn’t, snatching phones and those types of things," he said.
Some 200 officers from the first and 18th districts, some on foot and bikes, others on horseback, were ready.
“They went to the Red Line station at Chicago and State and when they came up from the subway station they were met with a large show of force," Ald. Brian Hopkins, 2nd, said.
For two hours, police worked to coral the unruly crowd, some disobeyed orders to disperse while others took off using CTA trains, Chicago Public Schools principals were also called in to try and help restore order.
“It’s crazy to think that that quickly, that many kids can group together and decide that they’re going to do something without anyone thinking maybe that’s not the best idea," grad student Abby Ohrnstein said.
In total, police said, 31 juveniles were arrested. All were charged with misdemeanors ranging from disorderly mob action to battery and CTA violations. Eventually, all were turned over to their families.
Two weeks ago several mob-like incidents popped up across the Mag Mile and River North, resulting in the arrests of 20 teens.
"Now, you will face consequences," Hopkins said. "You’ll end up in handcuffs in the back of a patrol car."
Police say there were no serious injuries in Wednesday night’s incidents but say they are taking a zero-tolerance approach to the unruly teen behavior. The arrests are meant to serve as a warning, police said.