The Trump administration asked the Supreme Court on Friday to allow construction of the White House ballroom to resume, one week after a federal appeals court ruled the $400 million project unlawful and ordered aboveground work to stop.

In a 45-page emergency application, Solicitor General D. John Sauer described the site as an integrated military complex that is "vitally required by national security," according to PBS. He asked the justices to act before the appeals court order takes effect Aug. 21.

The D.C. Circuit Court of Appeals ruled Aug. 7 that President Donald Trump lacked authority to pursue the 90,000-square-foot ballroom without congressional approval. The panel upheld a ruling by U.S. District Judge Richard Leon, a George W. Bush appointee, who found that pausing the project would not jeopardize national security and exempted work necessary for White House safety and security. The appeals court suspended its own decision for 14 days to allow an appeal.

The Supreme Court has asked for a response by midday Aug. 18. Construction may continue until the justices act or until the order takes effect.

The case is the first involving one of Trump's personal building projects to reach the Supreme Court. It stems from a lawsuit brought by the National Trust for Historic Preservation, which sued after the East Wing was demolished last fall without notice to Congress. The organization urged the justices not to permit construction to continue during the appeal, saying efforts to evade judicial review should stop, according to CNBC.

Trump initially described the ballroom as a venue for hosting foreign dignitaries and other guests. In recent months he and his aides have leaned on a national security rationale, pointing to a rooftop installation the president has called a drone port.

Friday's filing marked the administration's first confirmation that a threatened missile attack on Air Force One prompted the Secret Service to move Trump onto an alternate military aircraft to leave Turkey last month. The filing lists the July 8 threat among recent security incidents, Fortune reported.

The administration says the ballroom is roughly 65% complete after 10 months of construction.