Construction cranes being used for the White House ballroom are seen around the White House on March 23 in Washington. (AP Photo/Julia Demaree Nikhinson)

WASHINGTON (AP) — A federal judge on Tuesday ordered the Trump administration to suspend construction of a $400 million ballroom it demolished the East Wing of the White House to make space for, barring work from proceeding without congressional approval.

U.S. District Judge Richard Leon in Washington granted a preservationist group’s request for a preliminary injunction that temporarily halts President Donald Trump’s White House ballroom project.

The White House quickly filed a notice to appeal while Trump fumed at the ruling. “We built many things at the White House over the years. They don’t get congressional approval,” he told reporters in the Oval Office a short time later.

He also noted that the ruling will allow work on underground bunkers and other security measures around the White House grounds to continue — even though those will be paid for by taxpayers, not the private donors and Trump himself that the president has promised will cover the cost of the ballroom.

Leon, who was nominated to the bench by Republican President George W. Bush, concluded that the National Trust for Historic Preservation is likely to succeed on the merits of its claims because “no statute comes close to giving the President the authority he claims to have.”

“The President of the United States is the steward of the White House for future generations of First Families. He is not, however, the owner!” the judge wrote at the beginning of his opinion.

The ruling was the first major rebuke of Trump’s sweeping efforts to overhaul the White House. But it wasn’t immediately clear what it would mean for a sprawling project in which crews have long since torn down the East Wing, radically transforming the look and feel of the historic grounds.

The White House has only released a partial list of the companies and individuals donating to build the ballroom, and not said how much each is giving. Still, Trump rejected Leon’s ruling, saying, “This is being financed privately. It’s a donation.”

Construction of the ballroom would mark the most significant structural change to the White House since President Harry S. Truman added a balcony on the south side of the mansion.

The judge’s decision came two days before the National Capital Planning Commission, the agency that signs off on construction on federal property in the Washington region, is expected to approve the addition. Stephen Staudigl, a spokesperson for the commission, said the judge’s ruling does not affect the schedule for Thursday.

Carol Quillen, president and CEO of the National Trust for Historic Preservation, which filed the lawsuit prompting Leon’s ruling, said, “We are pleased with Judge Leon’s ruling today to order a halt to any further ballroom construction until the Administration complies with the law and obtains express authorization to go forward.”

“This is a win for the American people on a project that forever impacts one of the most beloved and iconic places in our nation,” Quillen said in a statement. The group had sued in hopes of obtaining an order pausing the ballroom project until it undergoes multiple independent reviews and receives congressional approval.

The judge suspended enforcement of his order for 14 days, acknowledging that the case “raises novel and weighty issues, that halting an ongoing construction project may raise logistical issues.” He also recognized that the administration would appeal his decision.