JACKSON, Miss. (AP) — Civil rights advocates say harsh discipline at many Mississippi schools leads to children being expelled and even incarcerated for minor infractions.

The groups say in a joint report that those policies disproportionally affect minorities.

The report says the problems are more widespread than just in the city of Meridian, where the U.S. Justice Department has filed a suit claiming officials are running a "school-to-prison pipeline" for minor infractions.

The groups, including the American Civil Liberties Union and the National Association for the Advancement of Colored People, plan to discuss their report at a news conference Thursday.

The report says many schools in Mississippi use zero-tolerance policies to lock up students or expel them l for relatively minor infractions.

The defendants in the Meridian lawsuit deny the Justice Department's allegations.