The U.S. Supreme Court temporarily blocked the deportation of Venezuelan migrants on Saturday morning, following a legal challenge that argued the men were at imminent risk of being deported without the required judicial review.

In a brief, unsigned ruling, the Court ordered the government to halt the removal of any detainees from the group in question until further notice. The White House did not immediately respond to requests for comment.

Justices Clarence Thomas and Samuel Alito dissented from the decision, which was issued around 12:55 a.m. (0455 GMT).

The American Civil Liberties Union (ACLU) filed urgent petitions on Friday, seeking immediate intervention after reports surfaced that some detainees had already been put on buses and told they were being deported. The ACLU argued that the government was using a 1798 wartime law to remove the individuals without offering them a proper chance to contest their deportation, as previously required by the Supreme Court.

“These men were at risk of being sent to foreign prisons for life without ever having their day in court. We are relieved the Supreme Court has stepped in to prevent their swift deportation, as others were recently subjected to,” said Lee Gelernt, lead attorney for the ACLU.

The case raises concerns about the Trump administration’s adherence to the Supreme Court’s limits, potentially setting the stage for a major constitutional clash between the executive and judicial branches of government.

President Trump had invoked the 1798 Alien Enemies Act to expedite the deportation of individuals linked to Tren de Aragua, a criminal gang from Venezuela that his administration has labeled a terrorist group.