Hundreds of people gathered in downtown Chicago on Saturday, prompting the closure of Michigan Avenue and drawing a large police response to the area near Millennium Park.
According to a traffic alert on sigalert.com, "several hundred youths were attempting to throw a party in Millennium Park," with fights and property damage reported in the area.
Police temporarily closed Michigan Avenue between Madison and Randolph streets, and access to the city's Christmas tree at Millennium Park was also blocked off as a precaution.
Crowds had largely dispersed by 10:30 p.m., and no arrests were made, according to Chicago police.
Multiple CTA bus routes were temporarily rerouted, according to tweets from the transit agency.
Further details on the incident were not immediately available Sunday morning.