CHICAGO (AP) — Illinois is among 19 states suing over the Trump administration’s effort to change a federal agreement limiting how long migrant children can be detained.

Attorneys general in California and Massachusetts are leading the effort and filed the lawsuit Monday.

A longtime agreement known as the Flores settlement says immigrant children must be kept in the least restrictive setting and generally shouldn’t spend more than 20 days in detention. The Trump administration says it plans its own set of regulations allowing longer detention of immigrant families.

A judge must OK the proposed changes to end the Flores agreement.

Illinois Attorney General Kwame Raoul says in a statement that “every American should be outraged” by the treatment of migrant children at the border.

Other involved states include Michigan and Minnesota.