Police say a large group of young people made their way down the Magnificent Mile and began fighting among themselves at 7:30 p.m.
Police responded quickly after the disturbance broke out, arresting a number of offenders in relation to the disturbance. The majority of them were juveniles.
There were no reported robberies, assaults or property damage related to the incident, according to police. However, witnesses say that some in the group scuffled with police.
The 17 arrested have been charged with misdemeanor reckless conduct.
"This was a planned attack," said community activist Andrew Holmes. "You had these many people down here and that many people just running from one side of the street, jumping on people on the east side, then they come back on the west side and jump on the people."
Holmes said that hundreds of teenagers took over the sidewalks on Chicago Ave., terrorizing shoppers.
"You had over 300-400 teens just walking the streets," Holmes said. "Some of the citizens just enjoying the nice day out. You had a lot of mob action going on, but I'm shocked by the amount of the women teenagers that were assaulting people."
Residents and shoppers expressed concern on Saturday night.
"The parents need to disciplining their children a lot more. That way, they wouldn't have come out into the streets like this, I think it's just absolutely ridiculous," said Derek Burns.
"I think it's horrible," said Doreen Cohen. "I don't understand why this keeps happening, I really don't."
