The U.S. Air Force is seeking to assert control over as much as two-thirds of a wildlife refuge in Nevada for training troops and testing weapons, according to a legislative proposal sent by military planners to the Department of the Interior and obtained by The Washington Post.

The military’s Nevada Test and Training Range already encompasses much of a vast stretch of southern Nevada desert originally set aside for bighorn sheep, desert tortoises and other wildlife. But the U.S. Fish and Wildlife Service retains primary authority over the refuge to halt military drills that would otherwise disturb key habitat for plants and animals.

The draft legislation would instead carve out 1.1 million acres of Desert National Wildlife Refuge to be used “primarily for the military purposes” and only “secondarily” as a nature preserve. The military wants to add as much as 260,000 acres of the refuge — the largest in the contiguous United States — to the testing range.

In a statement, the Air Force said it is working with Interior officials to amend the proposed legislation and the version obtained by The Post is “not the current draft.”

The Air Force says it needs the extra space as a safety buffer for the testing of new and more powerful weapons and no new areas would be bombed, adding it plans to physically disturb no more than 35 acres in the expanded range.

“The Air Force has conducted a four year process which included all identified stakeholders to examine the best way to meet the emerging test and training requirements,” it said.

Melissa Brown, an Interior Department spokeswoman, also suggested the draft legislation would be changed before being sent to Congress for inclusion in the next annual defense policy bill, known as the National Defense Authorization Act. “The proposals submitted for the 2021 NDAA are being reviewed and will inevitably change as it goes through the process,” she said.

But the draft bill, which is subject to changes by Interior officials before being submitted to Congress, gives the military the authority to do much more than just expand its testing grounds. It would jettison an environmental review that has happened every 20 years and exempt the area from wildlife refuge law, opening the way for the Air Force to mine sand, gravel and other materials from within the refuge for construction.

Some nearby residents, environmental groups and Native American tribes worry the proposal — outlined by the Air Force late last year but fleshed out in detail in the military’s draft bill — would render much of the desert wilderness north of Las Vegas a refuge in name only.

Jenny Keatinge, a federal lands policy analyst at the nonprofit Defenders of Wildlife who reviewed the draft bill, said it would “pull the teeth out of refuge law.”

“The Air Force’s damaging proposal represents not just an existential threat to Desert National Wildlife Refuge, but to the integrity of the refuge system itself,” she added.

The push to expand military testing in the refuge has sparked fierce opposition from Moapa Band of Paiutes, whose ancestral lands extend across the testing range and refuge, as well as beyond Nevada.

Last year, the tribe adopted a resolution outlining its objections, which included concerns about how the move would curtail access to sacred sites, damage cultural artifacts and harm desert bighorn sheep with which tribal members share a strong connection.

Greg Anderson, who chaired the tribe last year and served on its tribal council for the preceding five years, said in a phone interview that Air Force officials have consulted with tribal officials but have failed to carry out their pledges to protect sensitive sites in the past. He pointed to Pintwater cave, a site on the tribe’s former lands on which ordnance has been dropped.

“You can see the projectiles in the walls,” Anderson said, adding that incidents like that have prompted him to mistrust the Air Force’s promises. “They’re not doing what they’re saying they’re doing.”

The fact that the tribe’s 358 members will have to get special clearances to access sacred sites, he added, is equally problematic. “They’ve already taken away all our land,” Anderson said, referring to the 2.3 million acres the Moapa Band of Paiutes used to control.

In the resolution, the tribe noted its creation stories describe how its people entered the mountains and left as sheep. “In essence the sheep are people,” it states. “It is our duty to protect the mountain sheep for if they die, then we die too.”

Redefining protections on the Desert Refuge comes at a time when the Trump administration is trying to build a border wall through refuges in Texas and Arizona and open the Arctic National Wildlife Refuge to oil and gas drilling.

The political battle over this vast stretch of southern Nevada desert will ultimately be waged 2,000 miles away, in Congress. The Nevada congressional delegation, composed mostly of Democrats, is still grappling with how to handle the proposal.

Rep. Steven Horsford (D), whose district encompasses the refuge, is vehemently against the proposal. “I will do everything in my power to preserve this untouched habitat,” he said.

But the state’s senior senator, Catherine Cortez Masto (D), has left the door open to expansion while expressing concern for environmental and tribal interests.

“She continues to work with stakeholders to ensure the final proposal brought before the Senate respects the voices of local and Native communities, protects Nevada’s public lands and outdoor recreation economy, and honors our commitment to supporting our armed forces,” Cortez Masto spokeswoman Monica Garcia said.