The Trump administration has been ordered to stop construction on President Donald Trump’s $400m (£297m) ballroom at the White House.A federal appeals court dealt the latest setback to the controversial project on Friday, testing Trump’s presidential authority and paving the way for a Supreme Court showdown on appeal.“Whether or not a massive ballroom should be constructed is for Congress to decide and is not a matter for Executive self-help,” the panel’s majority said.The order upholds a preliminary injunction won by the National Trust for Historic Preservation, which sued after the administration tore down the East Wing last year to begin the project without congressional approval.“Congress has not ceded unfettered authority to the Executive Branch to dramatically redesign, reshape, and reconstruct the White House — the People’s House — to fit a particular President’s desires,” the panel said.The three-judge panel, in a 2-1 decision, said: “Each President is a temporary tenant, not the owner, of the White House and its Executive Residence.”“The President has no — and claims no — constitutionally assigned authority over that property, which is designed and maintained for the use of all Presidents, current and future, and for the American people,” the opinion said.The administration appealed to the court after a federal judge twice blocked above-ground construction on the ballroom, while still allowing underground work to proceed.The ruling on Friday upholds that order blocking above-ground construction without congressional approval. The appeals court delayed implementation of its ruling for 14 days to allow the Trump administration to appeal to the Supreme Court.The BBC has contacted the White House and Department of Justice for comment.Construction at the site where the East Wing previously stood was previously ordered to stop, but a court delayed the ruling allowing construction to continue while the appeals court considered briefs and heard arguments last month, according to the BBC’s US media partner CBS.President Trump has asserted that the new ballroom is needed to “accommodate people for grand parties, State Visits”, and has also said that it is “vital for National Security”.He doubled down on the need for the space after an assassination attempt at the White House Correspondents’ Association dinner in April.The three-judge panel on Friday said that its ruling “has nothing at all to do with whether the proposed ballroom is desirable”, nor does it weigh in on whether the administration may ultimately construct the ballroom.“What it does mean is that the Defendants may not do so during the district court’s expeditious litigation without securing Congress’s authorization, as the Constitution and laws require,” the order said.The National Trust for Historic Preservation celebrated the latest ruling, noting that no above-ground construction can take place “unless and until” Congress takes action.“The White House, a global landmark that symbolizes American identity and the ideals of democracy, belongs to the American people,” said Brent Leggs, President and CEO of the National Trust.“The National Trust for Historic Preservation and its partners are proud to defend this irreplaceable monument on behalf of all Americans.”