President Donald Trump said in a Truth Social post Sunday that he would convert plans for a Washington, D.C.-area “Triumphal Arch” to those for “a top grade Military Complex/Triumphal Arch” at the request of the U.S. military, citing “national security.”

The new plan, he said, is to “house, store, and have the rapid ability to use large numbers of drones, plus Snipers, on both the roof and plaza areas, and additionally have and hold large quantities of sniper ammunition in storage.”

Reached for comment, a Pentagon spokesperson said the department has “nothing additional to provide beyond the post.” The White House declined to provide additional information.

His post marked a significant change in plans that had already been in progress, as the Trump administration had announced earlier this month that it was preparing to break ground in the coming weeks.

The president’s announcement was also the second time he has framed a controversial construction project as a national security endeavor. Trump previously argued that the White House ballroom construction was necessary for national security and tied the project to an underground military complex.

The ballroom, too, has faced legal pushback, though the Supreme Court ruled at the end of August that the administration could move forward on ballroom construction indefinitely. The National Trust for Historic Preservation sued over the ballroom, arguing that Trump did not have the unilateral ability to undertake the project. The Supreme Court, though, ruled that the trust likely did not have proper standing to bring the case forward.

In early April, the White House argued to a federal appeals court that the project, including the ballroom, was “necessary to ensure the safety and security of the White House and its grounds.” Weeks later, a gunman stormed a security checkpoint at the White House Correspondents’ Association dinner, prompting the president to issue renewed calls for a White House event space. The annual dinner is hosted by the White House Correspondents’ Association, not the White House.

The proposed 250-foot arch project, which would sit in a roundabout between the Lincoln Memorial and Arlington National Cemetery, has faced legal challenges from veterans and historians. The project area sits on the Potomac, across from Washington.

The arch proposal has already passed key hurdles, though it’s unclear how Trump’s announcement could affect the prior approvals. In April, the project obtained approval from the Commission of Fine Arts, which is now composed of the president’s allies after he fired previous members. In July, the National Capital Planning Commission, which is led by Trump appointees, approved the preliminary site and building plans. The arch, which would sit a few miles from Reagan airport, also passed the Federal Aviation Administration’s air safety standards last week, with the administration announcing that it “would not pose a hazard to aircraft.”

The project appeared poised to move forward imminently. Interior Secretary Doug Burgum announced on Sept. 3 that the administration was preparing to start excavation work “over the next two-week period.” U.S. District Judge Tanya Chutkan ordered the Trump administration to provide 48 hours’ notice before it starts “any activity” on the arch, other than work to determine whether there are archaeological resources on the proposed site.

Trump has made Washington-area construction projects a key priority during his second term. Besides plans for the ballroom and arch, the president also moved to renovate the Lincoln Memorial Reflecting Pool, added a White House helipad and pushed to fix fountains in the capital.

Following the renovation of the Reflecting Pool, chunks of the pool’s new coating floated to the surface and the water turned green with algae. Trump also repeatedly claimed, without evidence, that vandalism led to the damage.