(CBS) — The warmest day of the year so far brought hundreds of teens to Michigan Avenue on Saturday. Police were calling it “mob action.”

CBS 2 has learned about multiple incidents in at least four different locations along the Magnificent Mile and in the Gold Coast, yielding a slew of arrests. In all, 25 juveniles and three adults were charged.

Many innocent shoppers and tourists became caught in the middle of a very chaotic situation. Hundreds of teens littered Michigan Avenue and State Street near Chicago.

Things started turn bad around 6:00 p.m. Saturday, with teens purposely bumping into people, and causing fights among themselves.

Fifteen juveniles and two adults were arrested and charged with misdemeanor reckless conduct in connection with the incidents on Michigan Avenue.

Community activist Andrew Holmes witnessed some of the problems, while shopping with his family.

“You had a group of teens, close to maybe 500. They assaulted a Chicago police officer that was mounted on a horse and all of a sudden they assaulted a citizen walking the streets, just a normal citizen shopping and enjoying the weather,” said Holmes.

Later that night, a man was attacked around 10:45 p.m. while walking near Chicago and Dearborn. Sources said he was jumped and punched in the face by a group of teens. He was taken to Northwestern Memorial Hospital.

In a separate incident, a group of women said they were attacked by a mob of girls on the CTA Red Line. The women reported a robbery once they got off the train at the State and Monroe station. Eleven females were arrested—10 juveniles and one adult—and charged with battery. Two of the teens also were charged with strong-armed robbery.

“I caution those parents if their child has been arrested which numerous teenagers have been arrested tonight, that you need to think about your child. Just don’t say the Chicago police picked on your child, when we were watching all the assault going on, especially by teen women,” said Holmes.

A total of 28 arrests were made last night surrounding downtown disturbances involving teens. Of those arrests, 25 were juveniles.

Charges range from battery and strong-armed robbery to reckless conduct.

CBS 2 has learned since these charges are misdemeanors, many of those arrested have already been released on I-bonds.

Sources tell CBS 2 that much of this activity was planned weeks ago through social media.