Environmentalist and Indigenous groups are outraged after a video began circulating on social media showing construction crews bulldozing some of the Organ Pipe Cactus National Monument’s most iconic cacti in an effort to build President Donald Trump’s long-promised border wall.

While the footage only shows a bulldozer moving a fallen cactus out of the way, Kevin Dahl, the man who captured the video, told Newsweek he has photos showing the cacti standing before they were mowed down.

Dahl, the senior program manager for the National Parks Conservation Association (NPCA) in Arizona, said he was “heartbroken” and “outraged” by the loss of the saguaro cacti, which are widely admired for growing more than three arms.

“At that point, what they were doing was destruction, not construction,” he told the publication.

The conservation association program manager also took photos of cacti that were marked with spray paint. He believes the paint indicates that this cacti will be removed in the future.

The U.S. Army Corps of Engineers, which is working with the U.S. Customs and Border Protection agency to oversee the construction of the border wall, previously said that it would be “relocating” cacti, including Saguaro and Organ Pipe plants, not getting rid of them. However, a video posted to their website last month shows that the relocation process involves team members carefully removing a cactus plant with the help of an extraction tool, not bulldozing it over.

Following the viral video, CBP and the National Park Service released a joint statement about their efforts to manage “environmental resources and border security.”

“Over the last 10 years, CBP and NPS have worked closely together to identify strategies for protecting environmental resources within the parks by minimizing the footprint needed for border enforcement activities,” the statement reads.

It continues: “These strategies have been effective in not only protecting sensitive biological, cultural, and historical resources within the parks but have also been effective in increasing border security which allowed OPCNM to restore public access to a number of park areas after several years of closure.”

Dahl, however, is not convinced. He’s still investigating why construction crews are knocking down the Saguaro cacti rather than properly relocating them or letting them stand.

In the U.S., Arizona’s Organ Pipe Cactus National Monument is considered a protected space. It’s both a U.S. National Monument and a UNESCO biosphere reserve. For decades, archaeologists have used the land to help preserve 16,000 years of human history that the monument contains, while environmentalists have worked to protect its endangered species and cactus plants. The park has also been identified by local indigenous groups, including the Tohono O’odham Nation, as sacred land.

“We love these saguaros,” Dahl told news site Earther. “The Tohomo O’odham [tribe], in their taxonomy of life saguaros are very close to humans. And you know, they have a majestic presence, they are the iconic symbol of this part of the world. You know you’re someplace different when you’re in a saguaro forest.”

Trump’s insistence to deliver on his campaign promise to build a barrier along the border with Mexico could harm the land, despite its environmental, spiritual and historic importance. The White House has already started construction and has vowed to complete 450 miles of the wall before the 2020 presidential election.