WASHINGTON (AP) — The Supreme Court on Wednesday refused to allow Florida to enforce an immigration law making it a crime for people who are living in the U.S. illegally to enter the state. The high court’s action will keep the law on hold while a legal challenge continues. The court did not explain its decision and no justice noted a dissent.

The law, enacted this year, made it a crime for unauthorized migrants to enter the state. Challengers say immigration is a federal matter.

The case, brought by immigrant advocacy groups, raises questions about whether and how states can police illegal immigration.