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.

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

The Chicago Loop is expected to see its third large-scale protest this week against ICE raids and the Trump administration. It comes as ICE tactical teams are supposedly set to begin work in the city,

A large-scale protest denouncing President Donald Trump will take place in downtown Chicago Saturday as part of a national day of action called "No Kings."

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.

PHOTOS: Take a peek at life in the city through the eyes and lenses of the Block Club Chicago staff.

City officials confirmed reports that President Trump is sending ICE tactical teams to Chicago, the same move that sparked massive protests in Los Angeles.