<h1>Protesters block cars at immigration enforcement facility; authorities use chemical agent, make arrests amid tense new traffic stop operation</h1> Protesters attempted to block vehicles outside a federal immigration enforcement facility in a Chicago suburb, prompting authorities to deploy a chemical agent to disperse the crowd and make several arrests so vehicles could enter and leave. The demonstration followed a new enforcement operation targeting traffic stops in immigrant neighborhoods and heightened local opposition after a fatal encounter last week in which officers say a man who had entered the country illegally evaded arrest, dragged an officer and prompted an officer to fire, claiming fear for his life. Local officials and activists vowed resistance and called for scrutiny of enforcement tactics.