A federal judge on Friday paused the Trump administration’s efforts to fast-track the deportation of migrants who legally entered the United States through humanitarian parole programs, marking a win for immigrant rights groups who argued the policy was illegal and dangerous.

The ruling blocks a new tactic employed by the Trump administration: detaining immigrants outside court appearances and putting them into a sped-up deportation process known as expedited removal.

The ruling halted the Trump administration from pursuing the deportation of hundreds of thousands of migrants accepted into the United States, who now retain only minimal legal safeguards.