In a late-night order February 9, Judge Kenneth J. Gonzales temporarily blocked the transfer of three immigrants with a long-standing legal challenge against their “unconstitutionally prolonged” detention after fleeing Venezuela and seeking protection in the United States.

Immigrant rights groups sent a letter demanding access to people who have been sent there, saying the base should not be used as a “legal black hole.”

Trump has announced plans to house at Guantánamo Bay up to 30,000 immigrants suspected of being in the U.S. illegally.