Immigration enforcement officials have arrested almost 550 people in the Chicago area as part of an operation that began less than two weeks ago. The Department of Homeland Security announced the arrests Friday. The operation, called “Midway Blitz,” started Sept. 8 and has raised concerns among activists and immigrant communities. They report a noticeable increase in immigration enforcement agents. Officials say about 50% to 60% of the arrests were targeted, while the rest were collateral arrests. The operation follows similar efforts in Los Angeles and Washington, D.C., and has sparked controversy over its aggressive tactics.