President Donald Trump is arguing that another one of his projects around Washington, D.C., is being built for national security purposes, claiming that his proposed “Triumphal Arch” would also be used as a “top grade Military Complex.”

Trump posted on his social media platform Sunday that, at the request of the U.S. military, he has “agreed to convert the magnificent Triumphal Arch, planned since the Civil War Era many years ago, at the Receptive Circle adjoining the Arlington Memorial Bridge, into a top grade Military Complex/Triumphal Arch, 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.”

The Pentagon declined to comment in response to an ABC News request.

Trump’s post said the structure would be used for national security purposes, a statement that’s similar to his claim last month that the under-construction White House ballroom, which he had previously said was needed to host events, is required to build a “highly integrated military complex that incorporates a classical, but highly secured, ballroom and crucial national-security facilities.”

Trump touted the new arch project, saying, “There will be no facility like this anywhere in the World. Out of the 59 top cities and Capitals, Washington, D.C., IS THE ONLY ONE IN THE WORLD THAT DOES NOT HAVE A TRIUMPHAL ARCH, but it will now and, by far, the greatest of them all!”

Trump’s proposed 250-foot arch is currently facing legal challenges brought by some military veterans and preservationists.

The administration acknowledged last week that the arch, which would sit along the Potomac River at the foot of Arlington National Cemetery, would cause “adverse effects” on the setting and views along the river. But the administration also said those impacts “cannot be fully avoided” because the arch’s location is “central to the undertaking.”

A group of Vietnam War veterans who have sued to block construction of the arch asked a federal judge earlier this month to issue a temporary restraining order to prevent the administration from moving forward with excavation work on the project. The veterans suing over the arch have argued it would obstruct views of Arlington National Cemetery and can’t be built without congressional authorization.

The National Trust for Historic Preservation, which brought a case against the administration over the ballroom, said the administration’s rhetoric about the project is hyperbolic bluster, telling the justices last month that Trump is unilaterally overriding Congress and now racing to complete the project “to try to outrun judicial review.”