New York Police Department stop-and-frisk practices violate both the Fourth Amendment prohibition against unreasonable searches and seizures and the Fourteenth Amendment's equal protection clause because they disproportionately target blacks and Hispanics, Southern District Judge Shira Scheindlin held Monday.

In rulings the city immediately vowed to appeal, Scheindlin issued a preliminary injunction against stop-and-frisk encounters that violate the U.S. Constitution, ordered reforms of NYPD policies and practices, and appointed a monitor to oversee changes in the 35,000-officer department, a step dreaded by Mayor Michael Bloomberg and Police Commissioner Raymond Kelly.