SUNLAND PARK, New Mexico—We Build the Wall, a privately funded effort to build a barrier along the U.S.-Mexico border, was told to stop building on Tuesday.

The cease-and-desist order represents a new obstacle for the group and its founder, triple-amputee veteran Brian Kolfage. Kolfage’s crowdfunding effort became a cause célèbre on the right last December, when he rapidly raised $20 million on GoFundMe for the wall. So far they have built less than a half-mile of fence on the border.

Sunland Park Mayor Javier Perea said at a press conference the city issued a cease-and-desist order, saying it is in violation of city ordinances. George Cudahy, whose company owns the land where the wall is being built, submitted an application for a building permit last week. Sunland Park officials declared the application incomplete, Perea said, because it lacked a site plan development and included contradictory information around the construction.

For example, Perea said, city ordinances requires walls to be under six feet. The border stands at roughly 20 feet, with seven feet buried beneath the ground. Nor was a necessary environmental survey completed, he said.

"Safety is always a concern for the city of Sunland Park," Perea said.

Perea said that Cudahy and the group must come into compliance before they can resume construction.

We Build the Wall is actually constructed by Fisher Industries. President Trump reportedly urged the U.S. Army Corps of Engineers to award contracts to build a border wall to Fisher Industries, whose CEO is a Republican donor and frequent guest on Fox News.

The barrier lies about 60 feet on the U.S. side of the border. Land was leveled off early last week, with sections of the wall dropped into place on Friday evening. With the first piece erect, members of the We Build the Wall team high-fived each other, shouting "suck it losers!" into their cellphone cameras.

We Build the Wall’s director of building operations, Mike Furey, told The Daily Beast before the cease-and-desist order it was a “test to show the government.”

Kolfage fumed on Twitter after the order was issued, claiming that it was the result of “liberals trying to intimidate us!”

“BULLSHIT!” Kolfage tweeted. “They were on site on Friday and gave us green light to build!”

In a follow-up tweet, Kolfage urged his supporters to “keep donating.”

Kolfage and his allies had repeatedly stressed the need to keep the wall’s location a secret for as long as possible in order to circumvent legal challenges. In a March radio interview, Kolfage said he had to hide the location to avoid opposition from the American Civil Liberties Union.

“I wish I could name where it’s at, but we can’t name it because of the ACLU, these other liberals groups that want to sue us and impede our progress,” Kolfage said.

Furey bragged they caught the ACLU off guard: "We caught them all flat footed!”

GoFundMe eventually offered refunds to donors after Kolfage changed the terms of the fundraising pitch, announcing that he would instead move the money to a nonprofit, We Build the Wall.

A number of Trumpworld immigration hardliners soon joined to We Build the Wall’s board, including former Trump strategist Steve Bannon, former Milwaukee Sheriff David Clarke, and former Kansas Secretary of State Kris Kobach.

The GoFundMe donors who had kept their money began to grow nervous in early May, after We Build the Wall missed an April groundbreaking deadline without offering any proof that construction had started or announcing the wall’s location. On Twitter and Facebook, donors complained about a lack of updates from Kolfage’s group.

Donors were made more anxious by Kolfage’s earlier efforts. Before launching the GoFundMe, Kolfage ran a number of conservative Facebook pages that promoted hoaxes and were eventually kicked off the platform. Kolfage also raised money for veterans programs at hospitals, but the hospitals said they had no records of the program Kolfage had fundraised for actually taking place.