Construction crews began blasting sites within Arizona’s Organ Pipe Cactus National Monument as part of the construction of President Trump’s border barrier, and the affected areas include sites sacred to Native American groups, according to a congressman from Arizona and advocates.

The Organ Pipe Cactus National Monument is an internationally recognized biosphere reserve — meaning it has plants and animals so rare that the United Nations has given it a special designation. It includes about 330,000 acres of designated wilderness and is home to ancestral grounds sacred to the Tohono O’odham Nation, one of at least a dozen Native American groups that claim connections to grounds within the monument.

Rep. Raúl M. Grijalva (D-Ariz.), whose district includes the reservation, said crews this week began blasting through parts of Monument Hill, which includes a burial site for the Tohono O’odham Nation.

“The construction contractor has begun controlled blasting, in preparation for new border wall system construction within the Roosevelt Reservation at Monument Mountain," A U.S. Customs and Border Protection spokesperson said in a statement sent to The Post. “The controlled blasting is targeted and will continue intermittently for the rest of the month.”

Grijalva, chairman of the House Natural Resources Committee, visited the location ahead of the construction and described the site in a video posted to social media. Monument Hill, where he said explosions are now occurring, is a site where members of the Tohono O’odham Nation have buried members of opposing tribes.

“Where they were blasting the other day on Monument Hill is the resting place for primarily Apache warriors that had been involved in battle with the O’odham. And then the O’odham people in a respectful way laid them to rest on Monument Hill,” Grijalva said in a video posted on Sunday.

CBP said there is an “environment monitor” present during the construction work, as well as “on-going clearing activities,” but did not provide additional details.

Before his visit, Grijalva sent a letter to the acting head of the Department of Homeland Security, Chad Wolf, to express “serious concerns” about the construction project.

“Members of the Tohono O’odham Nation recently informed me that the Department of Homeland Security is not respecting tribal lands and sacred sites as they proceed with border wall plans and construction,” he wrote in the January letter. “I strongly urge DHS to conduct meaningful government-to-government consultation with the Tohono O’odham Nation about the DHS’s planned border wall construction.”

But Grijalva said no such consultation has taken place.

“There has been no consultation with the nation,” Grijalva told CBS News. “This administration is basically trampling on the tribe’s history — and to put it poignantly, its ancestry.”

Laiken Jordahl, who works on border issues at the Center for Biological Diversity, told The Post that crews have “butchered” parts of the mountain. “It’s completely different from what it’s been before — there’s a swath of land gone from right in the middle,” he said.

“[T]he Nation categorically opposes the barrier construction projects, because they directly harm and threaten both the lands currently reserved for the Nation … and its ancestral lands that extend along the international boundary in Arizona,” Ned Norris Jr., chairman of the Tohono O’odham Nation, said in an accompanying letter to CBP’s Tucson sector chief.

Grijalva told CBS News he has not received a response from DHS.

In addition to concerns about sacred grounds, environmental advocates — and members of the U.S. government — have warned about the potential destruction of other sites and wildlife in the area as a result of construction.

An internal National Park Service report obtained by The Post found construction of Trump’s wall could destroy up to 22 archaeological sites within Organ Pipe Cactus National Monument.

“In addition to the sacred sites like Quitobaquito Springs, the entire monument is ancestral lands. The tribe uses it to gather plants, they still actively use it for ceremony, the entire landscape is sacred to the tribe,” Jordahl said.

“They’re plowing over ancient saguaro cactuses, 200-year-old cactuses, chopped up like firewood — it’s appalling,” he added. “They are also sacred to the O’odham; they see them as the embodiment of their ancestors. So to see them turned into mulch — it’s deeply upsetting.”

Crews have cleared some plants, as well as the saguaros, and moved them to other locations as they work within the national monument, according to the Arizona Republic. But Jordahl shared images with The Post of some saguaros that he said have been destroyed.

He pointed to the Trump administration’s move to use its authority under a 2005 law to bypass environmental rules and other laws in its efforts to construct the border barrier — a decision he says enables it to disturb wildlife or sacred sites.

Grijalva cited the 2005 law in his January letter, too, which he said allows the administration to waive requirements such as tribal consultation.

“[T]his administration continues to use its waiver authority at an unprecedented and irresponsible rate: of the 21 times the waiver has been enacted since 2005, 16 of those instances have occurred in the last two and a half years,” he wrote.

Grijalva said he plans to hold a hearing this month on the border construction’s impact.

“There’s urgency, and time is of the essence in order to try to work with our friends in the O’odham Nation to preserve, conserve and leave the identity intact,” he said.

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