A federal judge found probable cause to hold the Trump administration in criminal contempt for ignoring his order barring the deportation of alleged Venezuelan gang members to a notorious El Salvador prison.

"The Court ultimately determines that the Government's actions on that day demonstrate a willful disregard for its Order, sufficient for the Court to conclude that probable cause exists to find the Government in criminal contempt," Judge James Boasberg wrote in a court opinion Wednesday.

"The Court does not reach such conclusion lightly or hastily; indeed, it has given Defendants ample opportunity to rectify or explain their actions," Boasberg wrote. "None of their responses has been satisfactory."

Boasberg gave the administration one week to submit a declaration explaining its plan to "purge" the contempt finding.

That means "voluntarily obeying the court order" by giving the deported people the opportunity to challenge their removal through proper legal proceedings, he wrote.

But if the government decides not to take that step, Boasberg said, it must instead file a declaration identifying the person or people who "made the decision not to halt the transfer" of the Venezuelans on March 15 and 16, in spite of the judge's orders.

If declarations are "unsatisfactory," the judge said that he will order sworn witness testimony or depositions conducted by plaintiffs' lawyers. He would then ask the Justice Department to prosecute contempt. If the DOJ declines to do so, or says it cannot, Boasberg will appoint another attorney to take over the prosecution.

The White House plans to seek "immediate appellate relief," communications director Steven Cheung wrote on X after the court opinion.

"The President is 100% committed to ensuring that terrorists and criminal illegal migrants are no longer a threat to Americans and their communities across the country," Cheung wrote.

American Civil Liberties Union lawyer Lee Gelernt, the lead attorney for the plaintiffs, said in a statement to NBC News that Boasberg is "rightly laser focused on the return of the individuals sent to the notorious Salvadoran prison with no due process and that also remains our concern."

Boasberg's opinion is the latest legal development stemming from the Trump administration's efforts to carry out mass deportations of undocumented immigrants.

Last month, Trump invoked a wartime law from 1798 known as the Alien Enemies Act to deport a group of Venezuelans who were alleged to be members of the gang Tren de Aragua.

Five of them, who all deny being gang members, swiftly filed a lawsuit seeking to block their removal from the U.S.

At a hearing soon after, Boasberg learned that flights carrying the Venezuelans may have already taken off, though the attorneys for the government did not share details at that time. The judge then issued a temporary restraining order blocking the removals, telling the government that they must comply with it — even if that meant turning the planes around in midair.

"Despite the Court's written Order and the oral command spelling out what was required for compliance, the Government did not stop the ongoing removal process," Boasberg noted in Wednesday's filing.

The Trump administration appealed the order up to the U.S. Supreme Court. In a 5-4 ruling earlier this month, the high court sided with the Trump administration in part: It allowed officials to use the Aliens Enemies Act for deportations, but required that the Venezuelans have the chance to bring their cases to court.

Boasberg wrote that that decision "effectively said that the Constitution flatly prohibits the Government from doing exactly what it did that Saturday, when it secretly loaded people onto planes, kept many of them in the dark about their destination, and raced to spirit them away before they could invoke their due-process rights."