Army Corps of Engineers grants permission for controversial Dakota Access pipeline crossing

The US Army Corps of Engineers have said it will approve a permit to allow for the completion of the controversial Dakota Access pipeline.

The US Government is set to allow the final phase of construction of the Dakota Access pipeline to begin as early as Wednesday, dealing a major blow to the Standing Rock Sioux tribe.

The decision sets the stage for a tense showdown at the site of the drilling, where indigenous and environmental activists have been camped for nearly a year.

But President Donald Trump has supported the 1,172-mile (1,886-kilometer) oil pipeline, which would snake through four US states, and ordered officials to reconsider.

The Army Corps of Engineers provided notice of its intention to grant a permit for the oil pipeline to cross the Missouri river in North Dakota in a letter to Congressman Raúl Grijalva, the ranking member on the House committee on natural resources. The decision follows Donald Trump's executive order in his first week in office to expedite the project.

The letter, revealed in court filings, states that the easement will be issued "no earlier than 24 hours" after the delivery of the letter, which is dated February 7. The letter also states that the army corps intends to waive the usual 14-day waiting period after congressional notification, meaning drilling could begin as early as Wednesday.

"The Obama administration correctly found that the Tribe's treaty rights needed to be respected, and that the easement should not be granted without further review and consideration of alternative crossing locations," the Guardian quoted Jan Hasselman, an attorney for the Standing Rock Sioux tribe, as saying.

"Trump's reversal of that decision continues a historic pattern of broken promises to Indian Tribes and violation of Treaty rights. They will be held accountable in court."

The decision marks a rapid reversal of the Obama administration's decision to halt the $3.7bn pipeline, which the Standing Rock tribe says threatens its water supply and sacred indigenous sites. The Obama administration declined to issue the easement in December and initiated an environmental impact study, a process that could have delayed the project for years.

The Trump administration is also canceling the environmental impact study, according to the court filings.

"I have determined that there is no cause for completing any additional environmental analysis," wrote Douglas W Lamon, the senior official performing the duties of assistant secretary of the army, wrote in a notice to the federal register.

Thousands of protesters had camped in freezing winter temperatures to block the pipeline's planned route, which the Standing Rock Sioux Tribe says creates a risk of water pollution and endangers areas with sacred historic sites and artifacts.

The standoff -- which included some 2,000 military veterans who joined the protest -- set off violent clashes with law enforcement as well as sympathetic demonstrations nationwide.