A federal judge blocked construction of President Donald Trump's proposed 250-foot arch for 14 days on Thursday night, within an hour of a federal panel giving the project its final approval after a marathon public hearing.

The National Capital Planning Commission voted 8-4 around 10:29 p.m. to approve the monument at Memorial Circle, at the western end of Arlington Memorial Bridge, after more than eight hours of public testimony from more than 120 citizens, many of them veterans, who lined up to plead with the panel to block it.

Within an hour, U.S. District Judge Tanya Chutkan, who is overseeing a lawsuit seeking to stop construction, ruled that the administration was prohibited from "initiating, making or otherwise effectuating" any "construction-related activity" near the proposed site. The Trump administration had said it might begin construction immediately after the final vote.

Opponents denounced the arch as a vanity project and argued it is illegal because it lacks approval from Congress, pointing to the Commemorative Works Act, which requires congressional authorization for new monuments in Washington. The administration counters that Congress authorized a monument at the site more than a century ago, when it approved a bridge across the Potomac River.

A National Park Service review released in August found the arch would have "adverse" effects on as many as 42 historic sites, including Arlington National Cemetery, the Lincoln Memorial corridor and Arlington House. Trump has said he wants the arch completed before he leaves office in two years, and the White House is eager to move forward before a new Democrat-controlled Congress takes power in January.

The administration has laid out an aggressive construction plan, with two 10-hour shifts a day, and the Interior Department said within half an hour of the commission's approval that it would move forward. The legal fight continues: veterans and preservationists argue the monument would disrupt the sightline of landmarks including the Lincoln Memorial and break the solemnity of funerals at Arlington National Cemetery.