Massachusetts Sen. Elizabeth Warren announced her opposition Tuesday to the military's plan to expand into the Desert National Wildlife Refuge north of Las Vegas. The military's proposal would withdraw nearly 300,000 acres from the largest wildlife refuge in the contiguous United States — home to bighorn sheep and cultural sites important to Paiute and Shoshone tribes. 

"I oppose military expansion into the Desert National Wildlife Refuge — we have a responsibility to protect these lands from environmental damage, and respect the communities and heritage they represent," Warren said in a statement from her campaign.

The U.S. Air Force, with a large footprint in Southern Nevada, is proposing a roughly 300,000-acre expansion of its 2.9 million-acre testing range to free up space for modern warfare simulations, where bombs are dropped from higher elevations and at greater distances. 

That proposal has faced opposition from conservationists, tribes and hunters worried it would undermine public access and wildlife protections. 

This summer, the Legislature passed a bipartisan resolution opposing the expansion, which could also give the military — not the U.S. Fish and Wildlife Service — primary jurisdiction over about 800,000 acres of the refuge. Congress must vote on whether to approve the expansion.

"I believe we need true and meaningful consultation with tribal nations, especially regarding projects that could put important cultural and ecological sites at risk," Warren said.