WASHINGTON (AP) — A federal judge must reconsider the possible national security implications of halting construction of President Donald Trump’s $400 million White House ballroom, an appeals court ruled on Saturday.

A three-judge panel from the U.S. Court of Appeals for the District of Columbia Circuit said it did not have enough information to decide how much of the project can be suspended without jeopardizing the safety of the president, his family or the White House staff.

The case was returned to the trial judge who, in a March 31 ruling, barred work from proceeding without congressional approval, but suspended enforcement of that order for 14 days. The appeals court extended that for three days, to April 17, to allow the Trump administration to seek Supreme Court review.

The panel instructed U.S. District Judge Richard Leon to clarify whether — and how — his injunction interferes with the administration’s plans for safety and security.

Government lawyers had argued that the project includes critical security features to guard against a range of possible threats, such as drones, ballistic missiles and biohazards and that holding up construction “would imperil the President and others who live and work in the White House,.”

Leon, in issuing the temporary pause, concluded that the preservationist group behind the legal challenge was likely to succeed because the president lacks the authority to build the ballroom without approval from Congress.

Leon exempted any construction work necessary to ensure the safety and security of the White House, but said he reviewed material the government privately submitted before determining that a halt would not jeopardize national security.

The Republican administration’s appeal cited materials that would be installed to make a “heavily fortified” facility and said construction included bomb shelters, military installations and a medical facility underneath the ballroom.

The appeals panel noted that much of the government’s concerns focused on that below-ground security work, which the White House argued was “distinct from construction of the ballroom itself and could proceed independently.”

Now, however, the White House seems to suggest those security upgrades are “inseparable” from the project as whole, the appeals court said, making it unclear “whether and to what extent” moving forward with certain aspects of the ballroom is necessary for the safety and security of those upgrades.