An employee of a Chicago daycare was arrested at work on immigration charges Wednesday, according to witnesses, reflecting the Trump administration's increasingly aggressive enforcement tactics.

The employee ran from the passenger seat of a car inside the Rayito del Sol Spanish Immersion Early Learning Center, said Alderman Matt Martin. She was detained between two glass doors at the entry while telling authorities she was a U.S. citizen. Authorities went inside to question several people around 7 a.m., when the facility opens.

The operation was unusual even under “Operation Midway Blitz,” which has resulted in more than 3,000 immigration arrests in the Chicago area since early September. Agents have rappelled from a Black Hawk helicopter in a middle-of-the night apartment building raid, appeared with overwhelming force in recreational areas and launched tear gas amid protests.

The several officers at Wednesday's arrest wore clothing that read “POLICE ICE,” identifying them as U.S. Immigration and Customs Enforcement officials, Martin said.

ICE and its parent agency, the U.S. Department of Homeland Security, did not immediately respond to a request for comment. Rayito del Sol, which operates eight locations in Illinois and Minnesota, also did not immediately respond to a request for comment.

Its school in Chicago's Roscoe Village closed for the day after the arrest.