South Dakota's Rosebud Sioux (Sicangu Lakota Oyate) Tribe president said the House of Representative's Keystone XL pipeline vote is an "act of war," the Summit County Citizen's Voice reports.

 President Cyril Scott told the publication that the House vote violates the 1851 and 1868 Fort Laramie treaties, which forfeited the Black Hills to the Sioux Nation.

"The House has now signed our death warrants and the death warrants of our children and grandchildren. The Rosebud Sioux Tribe will not allow this pipeline through our lands," he said in a statement. "We are outraged at the lack of intergovernmental cooperation. We are a sovereign nation and we are not being treated as such. We will close our reservation borders to Keystone XL. Authorizing Keystone XL is an act of war against our people."

It is unclear what, if any, steps the U.S. government would take if the Rosebud Sioux Tribe closed their borders to the pipeline project.

The proposed TransCanada Keystone XL pipeline would be routed across the present exterior boundaries of the Rosebud Sioux Reservation and Cheyenne River Sioux Reservation, reports Grand Island Independent.

"The Lakota people have always been stewards of this land," Scott said. "We feel it is imperative that we provide safe and responsible alternative energy resources not only to tribal members but to non-tribal members as well. We need to stop focusing and investing in risky fossil fuel projects like TransCanada's Keystone XL pipeline. We need to start remembering that the earth is our mother and stop polluting her and start taking steps to preserve the land, water and our grandchildren's future."

Scott and the Lakota people are not alone in their environmental concerns.

"Building an 800,000 barrel-per-day pipeline of the world's dirtiest oil will mean more tar sands dug up and burned, and more carbon pollution," 350.org environmentalists have stated on their website.

The House passed a measure Friday that will force approval of the pipeline.

The Senate bill to force approval of the pipeline is scheduled for a vote on Tuesday, Nov. 18.

According to Washington Post, White House officials indicate that President Barack Obama is likely to veto the legislation if it does pass the Senate.