Officers spotted the man with "police identifiers" leaving a parking garage around 5 p.m. in the 200 block of South Michigan Avenue, Chicago police said.

Chicago is an anchor city for the "No Kings" protests Saturday, and city officials said they are prepared for the crowds expected.

At 4 p.m. as protesters were gathering, a counterprotester came to the scene — prompting angry chants to erupt from the main protest.

Thousands of protesters marched in Chicago against Immigration and Customs Enforcement raids in their city and President Trump’s deployment of troops in Los Angeles.

RIPPLE EFFECT: Thousands of demonstrators marched through downtown Chicago on Tuesday, stopping traffic in the Loop and along DuSable Lake Shore Drive to protest the Trump administration’s immigration raids that have erupted in California and across the country.