A Native American tribe filed a last-ditch legal challenge on Thursday to block the $3.8 billion Dakota Access oil pipeline project after the company constructing it won federal permission to tunnel under the Missouri River.
"This administration (of President Donald Trump) has expressed utter and complete disregard for not only our treaty and water rights, but the environment as a whole," the Standing Rock Sioux Tribe said in a statement on their website.
The tribe and environmental activists have vowed to fight the 1,170-mile (1,885-km) Dakota Access Pipeline (DAPL), fearing it will desecrate sacred sites and endanger drinking water. Supporters say the pipeline will be a safer mode of transportation for the oil than rail or trucks.
Legal experts have said the tribe faces long odds in convincing any court to halt work on the pipeline, which is being led by Energy Transfer Partners LP and could now begin operation as soon as June.
The U.S. Army said on Wednesday it had granted the final permit for the pipeline after an order from Trump to expedite the project. The army owns the land through its Corps of Engineers.
Opponents of the pipeline were running out of options, the tribe's chairman, David Archambault II, conceded to Reuters in a telephone interview on Wednesday. But, he said, "That doesn't mean that it's over."
Public opposition has drawn thousands of people to the site, including politicians and celebrities. Large protest camps popped up nearby, leading to several violent clashes and some 600 arrests.
The opposition sensed victory last year when the administration of Democratic President Barack Obama delayed completion of DAPL pending a review of tribal concerns and in December ordered an environmental study.
But after Trump, a Republican, took office he issued an order to expedite both DAPL and to revive another multibillion-dollar oil artery, Keystone XL. The Obama administration had blocked that project in 2015.
(Reporting by Daniel Wallis; Editing by Bill Trott and Bernadette Baum)