Native American tribes took their fight to Washington on Thursday to stop development of a $3.7 billion oil pipeline, as Democrats in Congress urged the federal government to scrap construction permits and reconsider the project.
Representative Raul Grijalva of Arizona, the senior Democrat on the House Natural Resources Committee, called on the U.S. Army Corps of Engineers "to withdraw the existing permits for Dakota Access pipeline."
He said the agency should then initiate a new, "transparent permitting process" that includes "robust" consultation with tribes and environmental review. The underground pipeline would traverse both federally managed and private lands in North Dakota, South Dakota, Iowa and Illinois.
Spokesmen for the Corps of Engineers were not immediately available for comment.
Thousands of activists, including the Standing Rock Sioux of North Dakota, have been protesting the 1,100-mile (1,886-kilometer) project being developed by Energy Transfer Partners LP, arguing it poses an environmental risk to the tribe's water supply and would violate sacred sites.
Their encampment on the North Dakota prairie marked the largest Native American protest in decades.
Republicans control Congress, but several House Democrats organized a "forum" to provide a platform for Native American tribes to voice their opposition to the pipeline and the government's permitting process.
Proponents of the pipeline were not present.
In yet another fight, aboriginal tribes from Canada and the northern United States signed a treaty Thursday to scrap proposals to build more pipelines to carry crude from Alberta's oil sands. The Standing Rock Sioux tribe is among the treaty's signatories.
Grijalva said the pipeline threatened the natural resources of the Standing Rock Sioux and the project was part of a "long history of pushing the impacts of pollution onto the most economically and politically disadvantaged people and communities across this country."
Standing Rock Sioux Tribe Chairman Dave Archambault complained to the Democratic panel that there was no "meaningful consultation" before permits were issued to bring the pipeline through his tribe's territory.
Dallas-based Energy Transfer Partners has countered that worries about oil contamination to local waters in the Missouri and Cannon Ball rivers were "unfounded" and that the company would address safety concerns.
President Barack Obama is set to meet with Native American tribal leaders next week at the White House. On September 9, the administration temporarily blocked construction of the project to deliver transport oil.