A U.S. district judge in Miami has issued a temporary injunction stopping construction of a planned immigration detention facility in South Florida that critics have branded “Alligator Alcatraz,” according to the Associated Press. The order, handed down on Thursday, requires work on the project to cease immediately while the court reviews legal challenges brought against the center. The detention complex, intended to house immigrants awaiting federal proceedings, has drawn opposition from local activists who argue it would harm surrounding wetlands and wildlife. The judge—an Obama appointee—said the plaintiffs had raised substantial questions about possible environmental and procedural violations, warranting a pause in construction. Further hearings are expected in the coming weeks to determine whether the halt will become permanent.