Federal immigration agents, including ICE and Border Patrol personnel, deployed tear gas and other riot control weapons against protesters during enforcement operations in Chicago and Illinois beginning in September 2025. On October 14, 2025, Border Patrol agents pursued a vehicle on Chicago's East Side, using a precision immobilization technique (PIT maneuver) to stop it at the intersection of 105th and Avenue N, resulting in a collision. Two undocumented immigrants fled on foot and were arrested. When residents gathered to protest the operation, federal agents deployed tear gas, exposing 13 Chicago police officers to the gas. A federal judge issued a temporary restraining order on October 9 limiting crowd-control tactics, but subsequent court filings alleged violations occurring almost daily. An analysis of 28 protest events found seven instances of riot control weapons use without apparent threats and 19 instances of excessive force.