President Donald Trump's push to build a massive "triumphal arch" in Washington, D.C. has run into a new legal obstacle, with the project now headed for a major court battle, according to a report by The Washington Post.

On Saturday, the Commonwealth of Virginia and the District of Columbia government jointly filed a lawsuit against the Trump administration seeking to halt construction of the arch. The suit argues that the monument, planned to stand 250 feet tall, has been advanced on "flagrantly unlawful" grounds and that, if completed, it would permanently alter the "landscape" of the U.S. capital city.

"The lawsuit is the latest attempt to stop the 250-foot-tall arch, which Trump hopes to build near Arlington National Cemetery and says will commemorate the nation's 250th birthday," the Post's report detailed. "The administration would like to begin construction as soon as next week. The two jurisdictions are asking a federal judge to halt the plan and argue that they have 'indisputable standing' to bring their lawsuit because the towering arch would have tangible, negative effects on the region — an argument that distinguishes their lawsuit from others that have tried to stop Trump's construction projects."

According to the report, D.C. Attorney General Brian Schwalb (D) said the arch's construction would cause "serious, immediate and irreparable harm to the District and its residents," while Virginia Attorney General Jay Jones (D) described it as "Trump's illegal vanity project" that would be an affront to Arlington National Cemetery and the "extraordinary sacrifices it represents."

"The Commonwealth has a solemn duty and a profound interest in preserving the dignity of this sacred place," Jones said in a statement. "We will vigorously litigate to protect its sanctity and honor the legacy of those who made the ultimate sacrifice."

As the report noted, this suit is not the first legal battle the arch has faced. A separate lawsuit was filed by three Vietnam veterans and a "historic preservationist," with a federal judge indicating on Friday that they might side with the plaintiffs and block the project. The jurisdictions' filing arrived one day after that signal from the bench, giving opponents of the arch a second, independent avenue to challenge it in federal court.

"The administration has acknowledged that the arch will unavoidably harm local historic sites by altering views, and that it will divert traffic and create loud noise during years of planned construction, among other disruptions," the report added.

The administration has attempted to argue that the arch would also serve a "national security" function — an argument which, critics allege, Trump has become reliant on to try to force through his vanity projects. In a post on Truth Social, his social media platform, the president claimed that the arch could be used as a drone deployment location and a sniper's nest, as well as a storage facility for ammunition. Both cases now sit before federal judges as the administration presses toward its targeted start of construction.