The group that is relying on crowdfunding to pay for construction of a private border wall in South Texas has been ordered to stop the construction they began last week by U.S. officials who monitor compliance of an international water treaty.

“We sent a letter on Friday requesting they submit additional information about their activities and asked them to stop construction until we review that information,” said Sally Spener, a spokeswoman for the International Boundary and Water Commission. She did not indicate how long it would take to review the project, but did say the group informed her agency that it would provide the requested information.

The letter went to a controversial Florida-based group called We Build the Wall, Inc., which earlier this year built a one-mile stretch of wall on private property in New Mexico just across the border from El Paso. Their construction efforts there were also briefly put on hold because the city of Sunland Park, where they were building, said they did not get the proper building permits. Eventually they were allowed to complete the wall.

The group claimed last week that it was moving forward on the crowdfunded project along the Rio Grande in South Texas. On Thursday, heavy equipment could be seen clearing brush and cane along the river on private property near the town of Mission and adjacent to the National Butterfly Center. In a now-deleted video on Facebook, a man calling himself “Foreman Mike” with We Build the Wall, the Florida-based group behind the project in New Mexico, said the clear-cutting was the first step in building three-and-a-half miles of wall to help President Trump in his efforts to secure the border.

The brush removal began on Monday, the group said in its video. This would have marked the first known activity by We Build the Wall in Texas. Local environmentalists claimed a wall in the area would worsen flooding in Mexico, violating an international treaty and create additional hazards by building in a floodplain. “Private entities are not free to violate the treaty and endanger lives and property in Mexico,” said Scott Nicol, with the Sierra Club’s Borderlands Campaign. Nicol also noted that environmental regulations—waived by the U.S. Department of Homeland Security for federal wall construction—would still apply to private entities like We Build the Wall.

In the now deleted five-minute video, “Foreman Mike” said We Build the Wall needed to raise at least $1,000 a day to just pay for the fuel for the heavy equipment now clearing the land. Their overall fundraising goal was not immediately clear, and an email to the organization seeking elaboration went unanswered.

“Their wall is just a publicity stunt meant to fire up donors and pull in cash, but if they actually build a wall on the riverbank, it will be tremendously destructive,” Nicol warned. “They are building on a sandy riverbank, so when the first strong flood hits, the wall will wash away, sending a mass of concrete and steel downriver that will slam into homes and businesses. Their wall could not only destroy property, it could kill people.”

The construction was slated to happen in the congressional district of Congressman Henry Cuellar, D-Laredo. “No wall, whether funded by public dollars or private funding, is wanted on the border,” he told Texas Monthly.

Hidalgo County tax records show that the clear-cutting was on land—more than one thousand acres—owned by Neuhaus & Sons. Lance Neuhaus, the grandson of the founder of Texas State Bank, confirmed to Border Report that he had allowed We Build the Wall on his land, but wouldn’t elaborate.

On Thursday, to get a better look at the construction activity, I took a boat tour of the Rio Grande with Marianna Treviño-Wright, executive director of the National Butterfly Center, and Father Roy Snipes, whose La Lomita Chapel was also briefly threatened by federal wall construction plans before Congress intervened to protect that historic landmark.

From the river, it was evident that the clear-cutting came right down to the bank of the river, suggesting that the wall would be built much closer to the Rio Grande than much of the existing and planned border barriers. In the video, “Foreman Mike” says the wall would be built 25 to 30 feet from the Rio Grande. “Clearly they’re going to build on the banks of the river, but it will end up in the river when we have another tropical storm,” Treviño-Wright said. Snipes also questioned how stable the structure would be given the shallow water table that exists along the river.

In the video, We Build the Wall founder Brian Kolfage said they expected to complete the private wall in a month-and-a-half. He didn’t explain anything else about the design of the wall, and it was unclear how a private wall would integrate with the Trump administration’s plans for at least 88 miles of border barrier in the Rio Grande Valley. The Neuhaus property does not appear to be part of publicly disclosed maps depicting future border wall. Federal contractors have begun clear-cutting land about five miles west of the Neuhaus property, but construction has yet to begin. In contrast, two wall panels have been put into place at a site about thirty miles east of Mission, just south of Donna. An email seeking comment from Customs and Border Protection about We Build the Wall’s activities went unanswered. “Foreman Mike” appears in another Facebook video criticizing the federal effort.

We Build the Wall started as a GoFundMe effort last December when Kolfage, an Iraq veteran and triple amputee, sought to raise $1 billion. Within a month, the crowd-sourcing campaign had brought in more than $20 million from nearly 340,000 donors. In August, authorities in Florida said they had launched a criminal investigation into the nonprofit group. The status of that investigation is unknown, and Kolfage has denied any wrongdoing. The group’s efforts at building the wall near El Paso were temporarily halted because of city permitting issues. But construction of the half-mile barrier was eventually allowed when the group appeared to be in compliance with local ordinances.

Former White House advisor Steve Bannon and former Kansas secretary of state and outspoken immigration critic Kris Kobach are members of the group’s advisory board, according to We Build the Wall’s website.

This story was updated throughout on November 19, 2019, to reflect that We Build the Wall had been ordered to stop construction.