A federal judge in Denver on Tuesday granted a motion for a temporary restraining order blocking the removal of detainees held in Colorado under the 1798 law that President Donald Trump’s administration has invoked to send more than a hundred of people to a brutal maximum-security prison in El Salvador.

U.S. District Court Judge Charlotte Sweeney’s 35-page order came one day after an initial hearing in the case, which was brought as a petition for habeas corpus and proposed class action by lawyers for the American Civil Liberties Union, on behalf of two Venezuelan nationals held at the Immigration and Customs Enforcement detention center in Aurora.

Sweeney’s order, which will remain in effect until at least May 6, applies to the two plaintiffs and members of the class they seek to represent — “all noncitizens in custody in the District of Colorado who were, are, or will be subject to” Trump’s March 14 proclamation invoking the Alien Enemies Act of 1798. That could apply to more than 100 people detained at the Aurora facility, ACLU attorneys have estimated.

In addition to ordering that the Trump administration “shall not move Petitioners and members of the provisionally certified class outside the District of Colorado,” Sweeney instructed the government to begin giving at least 21 days’ notice to detainees targeted for removal under Trump’s proclamation.

“Such notice must state the government intends to remove individuals pursuant to the Act and Proclamation,” Sweeney wrote. “It must also provide notice of a right to seek judicial review, and inform individuals they may consult an attorney regarding their detainment and the government’s intent to remove them. Such notice must be written in a language the individual understands.”

Trump’s order invoking the Alien Enemies Act claims that the United States is under “invasion” by the Venezuelan gang Tren de Aragua. It was the basis for the deportation last month of 137 migrants to El Salvador’s so-called Terrorism Confinement Center, or CECOT, where the U.S. government is paying for them to be held. At least 11 deportees were previously held in Colorado, attorneys for the plaintiffs said after Monday’s hearing.

Trump has pledged to begin sending American citizens to the CECOT facility, criticized by human rights groups for its crowded and abusive conditions. About 90% of the deportees sent there last month had no criminal record. At least one, Kilmar Armando Abrego Garcia, was removed as a result of an “administrative error,” while advocates, attorneys and family members for many other deportees say that they were falsely identified as TdA members because of tattoos honoring family members or their favorite soccer team.

Other federal courts, including the U.S. Supreme Court, have ordered the Trump administration to halt Alien Enemies Act deportations and provide detainees the opportunity to contest their removal and alleged gang ties. But ACLU attorneys allege the administration is refusing to comply with that order and providing detainees with insufficient notice of 24 hours or less. Trump has also openly defied a Supreme Court order to “facilitate” the return of Abrego Garcia, leading some Democrats to declare a constitutional crisis.

Plaintiffs in the Colorado case are identified by their initials, D.B.U. and R.M.M. They both deny being members of TdA.

D.B.U. is a 32-year-old asylum seeker who has lived in Colorado with his wife and two children. R.M.M. is also a Colorado resident who is seeking asylum. He says that he fled Venezuela to escape TdA, which killed his wife’s father and uncle and which he fears will kill him and his wife and children.

Representing the Trump administration during Monday’s hearing, the office of the U.S. Attorney for Colorado argued that the court lacked jurisdiction in the case because ICE officials had determined that D.B.U. and R.M.M. are not covered by Trump’s proclamation. But the government’s attorneys could not rule out the possibility that that determination could change in the future, and Sweeney agreed with the plaintiffs that they had “shown a sufficient risk” of such a designation.

“It is not dispositive that D.B.U. and R.M.M. are not ‘currently’ designated as ‘subject’ to the Proclamation when the government may revise this designation at any time — and failed to eliminate that possibility, or the speed with which such re-designation could occur, when asked directly at oral argument,” she wrote.

“Practically speaking, a TRO would inflict little more on Respondents than ensure they adhere to the requirement the Supreme Court has already imposed on them: give Petitioners and putative class members adequate notice, with adequate time, to adequately pursue habeas relief,” Sweeney’s order added.

The U.S. Attorney’s office declined to comment Tuesday. Following the granting of the TRO, plaintiffs in the Colorado case are expected to file a motion for a longer-lasting preliminary injunction. Sweeney directed the plaintiffs to file such a motion, if they choose to do so, by Friday.

Echoing preliminary findings by other federal judges, including D.C. District Judge James Boasberg, Sweeney wrote that the ACLU’s challenge to the Alien Enemies Act removals are “likely to succeed on the merits.” The act has been invoked on only three previous occasions and only during war, most recently during World War II as the basis for the incarceration of noncitizens of Japanese, German and Italian descent.

The text of the act, passed during President John Adams’ administration at the height of an undeclared military conflict between the United States and France, refers to the “invasion” of or “predatory incursion” into U.S. territory.

“These words, fundamentally, demand military and wartime action,” Sweeney wrote. “The Proclamation makes no finding that satisfies these definitional demands. Thus, to the extent the Proclamation relies on the Act’s ‘invasion’ and ‘incursion’ provisions to justify its removal powers, it does so improperly.”

Editor’s note: This story was updated at 1:58 p.m., April 22, 2025, to clarify how many people have been deported under the Alien Enemies Act.

This article originally appeared in Colorado Newsline, which is part of States Newsroom.