A federal judge said on Monday that the White House had defied his order to release billions of dollars in federal grants, marking the first time a judge has expressly declared that the Trump administration is disobeying a judicial mandate.

The ruling by Judge John J. McConnell Jr. in Rhode Island federal court ordered administration officials to comply with what the judge called “the plain text” of an ruling he issued on January 29.

That order, he wrote, was “clear and unambiguous, and there are no impediments to the Defendants’ compliance”.

Shortly after Monday’s ruling, Trump administration lawyers appealed the judge’s initial order to the US Court of Appeals for the First Circuit, asking the appellate court to pause Judge McConnell’s order to keep federal funds flowing while their case was being considered. The White House responded with more defiance.

“Each executive order will hold up in court because every action of the Trump-Vance administration is completely lawful,” said Harrison Fields, a White House spokesman. “Any legal challenge against it is nothing more than an attempt to undermine the will of the American people.”

The legal actions on Monday marked a step towards what could evolve quickly into a high-stakes showdown between the executive and judicial branches, a day after Vice- President J.D. Vance claimed in a social media post that “judges aren’t allowed to control the executive’s legitimate power”.

Fields’s statement suggested that the President would ultimately prevail in court, but neither he nor the justice department explained what the White House would do in the meantime.

It appeared that the administration was trying to win through the legal system’s established procedures, even as officials questioned the legitimacy of those procedures from the outside.

To that end, some of Trump’s supporters accused the judges ruling against the President of overstepping their authority.

“Activist judges must stop illegally meddling with the president’s Article II powers,” wrote Mike Davis, who leads the Article III Project, a conservative advocacy group.

The Democratic attorneys general driving much of the legal pushback pressed their position.

“No administration is above the law,” said Rob Bonta, the attorney general of California, in a statement shortly after Monday’s order. “The Trump administration must fully comply with the court’s order.”

Already, more than 40 lawsuits have been filed to challenge Trump’s moves.