WASHINGTON — The Trump administration said Monday it is pausing construction of a contentious border construction project in Texas’ Big Bend National Park while the head of the agency tasked with building the wall visits to do an “on-the-ground evaluation.”

The project through the national park in southern Texas has faced fierce bipartisan opposition by critics who say it is marring the area’s pristine environment. They argue the region’s rugged and remote terrain already serves as a deterrent to migrants and smugglers. Border crossings in the area have historically been lower than other regions and have dropped even further over the past two years.

“CBP is pausing all construction activity in Big Bend National Park while I visit and conduct a personal, on-the-ground evaluation,” Rodney Scott, who heads Customs and Border Protection, said on X. Scott said over the next couple of days, he was going to “listen to local leadership, community members and stakeholders” to address what he said were “real” national security threats while protecting the park.

While it isn’t clear whether the brief suspension portended a more lasting halt to the construction in the area, it reflected the intensity of the bipartisan opposition and was a rare concession from the administration on a signature promise of the president’s that it has raced to complete.

Congress gave the Trump administration $46 billion last summer to build a wall from the Pacific Ocean to the Gulf of Mexico, and the administration has been charging ahead and waiving numerous regulations in an effort to swiftly build the wall.

Scott has said that he expects the first layer of the wall to be built by the end of next year.

But the administration has run into fierce opposition in Texas especially when it comes to construction in and near Big Bend National Park and a state park to the west.

Customs and Border Protection earlier this year backed off plans to build a 30-foot tall-bollard wall through the parks but was still moving forward with other border protection measures such as a new road, lights, miles of barriers designed to stop cars from crossing the border and technology such as fiber optic cables to be buried under the fences.

That has sparked opposition from Democratic and Republican sheriffs in the region, former national park officials, local residents who rely on the parks for their livelihood and from some Texas elected officials. Critics have said it will scar the rugged landscape that attracts tourists who raft down the Rio Grande and take advantage of some of the clearest night skies in the U.S. to gaze at stars.

Last week, bulldozers were seen clearing land at the park, sparking even more concern and raising questions from one of the state’s Republican senators. Sen. John Cornyn, who lost the Republican primary to the state’s attorney general, wrote to Homeland Security Secretary Markwayne Mullin over construction concerns.

“My constituents believe that the 1,000-foot riverbank cliffs and remote Big Bend terrain offers its own source of deterrence for any illegal migrants crossing into the United States. The dangerous terrain includes steep mountains, deep canyons, and expansive deserts which they believe act a natural barrier that limits large-scale movements,” Cornyn wrote.