MILWAUKEE (AP) — The American Civil Liberties Union in Wisconsin is alleging in a lawsuit that Milwaukee police are operating a stop-and-frisk program mostly targeting black and Latino residents who are often detained without cause.The lawsuit being filed in federal court Wednesday is on behalf of six black and Latino plaintiffs who say they’ve been stopped once or multiple times without a citation or clear explanation for why they were detained. The lawsuit alleges the stop-and-frisk program is citywide but is concentrated in areas largely populated by minorities.

Milwaukee police did not immediately respond to a request for comment.

The ACLU has challenged similar police initiatives in Boston and Chicago over racial-profiling concerns. New York halted its stop-and-frisk policy in 2014 after a federal judge ruled it unconstitutional.