(CNN) The controversial Dakota Access Pipeline project -- bitterly opposed and vilified by Native Americans and environmentalists -- might be a big step closer to fruition.

But a tribe fighting the pipeline is moving full-steam ahead in court to stop the project.

The US Army Corps of Engineers granted an easement in North Dakota for the pipeline, a move enthusiastically greeted by the project builders.

Work would start "immediately," said Vicki Granado, spokeswoman for Energy Transfer Partners, the parent firm of the company building the pipeline.

"Dakota Access now has received all federal authorizations necessary to proceed expeditiously to complete construction of the pipeline," Energy Transfer Partners said in a statement.

But the Standing Rock Sioux Tribe and its allies say the easement shouldn't have been granted without the issuance of an environmental impact statement, or EIS for short.

"The Trump administration may have announced termination of the EIS, but that will not go unchallenged. This administration has expressed utter and complete disregard for not only our treaty and water rights, but the environment as a whole," the tribe said in a statement.

Trump's executive action

The fate of the project changed after the election of President Donald Trump.

Trump signed executive actions a few weeks ago to advance approval of the pipeline. His flick of a pen cast aside efforts by President Barack Obama's administration to block construction.

Trump's order directed "the acting secretary of the Army to expeditiously review requests for approvals to construct and operate the Dakota Access Pipeline in compliance with the law."

Acting Secretary of the Army Robert Speer's moves to grant the easement and stop the preparation of an environmental impact statement were anticipated.

"The decision was made based on a sufficient amount of information already available which supported approval to grant the easement request," the Army said Tuesday.

Speer called granting the easement a "final step" in meeting the tasks of the President's executive action.

The Standing Rock Sioux tribe, which has long opposed the part of the project near its home, plans argue in court that the environmental impact statement process was wrongfully terminated.

The tribe is demanding a proper environmental impact statement to identify risks to its treaty rights, including its water supply and sacred places.

It wants disclosure of oil spill and risk assessment records, and it will seek to shut down down pipeline operations if the construction is successful.

The tribe said the Obama administration had determined other locations for the pipeline, and those should be looked into by the Army.

"The Obama administration correctly found that the Tribe's treaty rights needed to be acknowledged and protected, and that the easement should not be granted without further review and consideration of alternative crossing locations," said Jan Hasselman, lead attorney for the tribe.

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

Photos: North Dakota pipeline protests Photos: North Dakota pipeline protests Fireworks lit the sky at the Oceti Sakowin Camp near Cannon Ball, North Dakota on December 4, 2016, after the Army Corps of Engineers halted the Dakota Access Pipeline route. An executive order by President Donald Trump in January allowed work to resume. Hide Caption 1 of 32 Photos: North Dakota pipeline protests Activists embrace after the December halt of the Dakota Access Pipeline route. The $3.7 billion project that would cross four states and change the landscape of the US crude oil supply. The Standing Rock Sioux tribe says the pipeline would affect its drinking-water supply and destroy its sacred sites. Hide Caption 2 of 32 Photos: North Dakota pipeline protests An activist rides down from a ridge on the edge of the Standing Rock Sioux Reservation on December 4. Hide Caption 3 of 32 Photos: North Dakota pipeline protests Activists celebrate at Oceti Sakowin Camp on December 4. An executive order by President Donald Trump in January allows work to resume on the Dakota Access Pipeline, which the activists oppose. Hide Caption 4 of 32 Photos: North Dakota pipeline protests Dan Nanamkin of the Colville Nez Perce tribe drums a traditional song by the Cannonball River in Cannon Ball, North Dakota, on Thursday, December 1. Hide Caption 5 of 32 Photos: North Dakota pipeline protests A procession makes its way down to the Cannonball River to take part in a Native American water ceremony on December 1. Hide Caption 6 of 32 Photos: North Dakota pipeline protests Snow covers the camp on Wednesday, November 30. Hide Caption 7 of 32 Photos: North Dakota pipeline protests A person walks through snow and wind on Tuesday, November 29. Hide Caption 8 of 32 Photos: North Dakota pipeline protests People against the construction of the Dakota Access Pipeline speak at a news conference near Cannon Ball on Saturday, November 26. Hide Caption 9 of 32 Photos: North Dakota pipeline protests A sculpture stands at an encampment where protesters of the pipeline have been gathered for months. Hide Caption 10 of 32 Photos: North Dakota pipeline protests People protest along Highway 1806 as they walk past a sprawling encampment on Thursday, November 24. Hide Caption 11 of 32 Photos: North Dakota pipeline protests A man stands along Highway 1806 on November 24. Hide Caption 12 of 32 Photos: North Dakota pipeline protests In this image provided by the Morton County Sheriff's Department, law enforcement and protesters clash near the pipeline site on Sunday, November 20. Hide Caption 13 of 32 Photos: North Dakota pipeline protests Tonya Stands recovers after being pepper-sprayed by police on Wednesday, November 2. Stands was pepper-sprayed after swimming across a creek with other protesters hoping to build a new camp to block construction of the Dakota Access Pipeline. Hide Caption 14 of 32 Photos: North Dakota pipeline protests Dozens of protesters wade in cold creek waters as they confront local police on November 2. Hide Caption 15 of 32 Photos: North Dakota pipeline protests Tribe members make their way back to their camp on Saturday, October 29. Hide Caption 16 of 32 Photos: North Dakota pipeline protests Cousins Jessica and Michelle Decoteau take part in a protest outside the North Dakota state capitol in Bismarck on October 29. Hide Caption 17 of 32 Photos: North Dakota pipeline protests The burned hulks of heavy trucks sit on Highway 1806 on Friday, October 28, near a spot where Dakota Access Pipeline protesters were evicted a day earlier. Hide Caption 18 of 32 Photos: North Dakota pipeline protests Pipeline protesters sit in a prayer circle as a line of law enforcement officers make their way across the camp to relocate the protesters a few miles south on Thursday, October 27. Protesters had camped on private property. Hide Caption 19 of 32 Photos: North Dakota pipeline protests A protester is arrested as law enforcement surrounds the camp on October 27. Hide Caption 20 of 32 Photos: North Dakota pipeline protests Tires burn as armed soldiers and law enforcement officers stand in formation to force Dakota Access Pipeline protesters off the private land in Morton County. Hide Caption 21 of 32 Photos: North Dakota pipeline protests A protester shows where he was hit by a bean-bag round fired by officers trying to force protesters off the private land. Hide Caption 22 of 32 Photos: North Dakota pipeline protests JR American Horse leads a march to the pipeline site on Friday, September 9. Hide Caption 23 of 32 Photos: North Dakota pipeline protests Native Americans head to a rally at the state capitol in Denver on Thursday, September 8. They were showing their support for members of the Standing Rock Sioux tribe in North Dakota opposting the Dakota Access Pipeline. Hide Caption 24 of 32 Photos: North Dakota pipeline protests People hang a sign near what they say was sacred burial ground disturbed by bulldozers in Cannon Ball. Hide Caption 25 of 32 Photos: North Dakota pipeline protests Marlo Langdeau of the Lower Brule Sioux Tribe joins hundreds of Native Americans for a march near Cannon Ball on Sunday, September 4. Hide Caption 26 of 32 Photos: North Dakota pipeline protests Protesters march on September 4 in opposition to the Dakota Access Pipeline. Hide Caption 27 of 32 Photos: North Dakota pipeline protests Native Americans march to the site of a sacred burial ground on September 4. Hide Caption 28 of 32 Photos: North Dakota pipeline protests Native Americans ride with raised fists to the sacred burial ground on September 4 to protest the Dakota Access Pipeline. Hide Caption 29 of 32 Photos: North Dakota pipeline protests The Missouri River is seen beyond an encampment near Cannon Ball, where hundreds of people gathered to join the protest on September 4. Hide Caption 30 of 32 Photos: North Dakota pipeline protests Flags of Native American tribes from across the United States and Canada line the entrance to a protest encampment on Saturday, September 3. Hide Caption 31 of 32 Photos: North Dakota pipeline protests Phil Little Thunder Sr. attends an evening gathering at an encampment of Dakota Access Pipeline protesters on September 3. Hide Caption 32 of 32

The decision gives the pipeline's developer -- Dakota Access, a subsidiary of Energy Transfer Partners -- right-of-way through government land at Lake Oahe Dam and Reservoir in North Dakota.

The tribe has been concerned that digging the pipeline under Lake Oahe -- a section of the Missouri River in North Dakota -- would affect the area's drinking water, as well as the supply for 17 million people living downstream.

The proposed underground route at Lake Oahe is half a mile upstream from the tribe's reservation.

Greenpeace said the President was looking out for the rich.

"We are less than two weeks into this administration, and already Trump has put on full display a blatant disregard for Indigenous sovereignty, public health, and public outcry," the environmental organization said. "This decision to smash through the (environmental impact statement) process is nothing but a reward to Trump's corporate, oil industry cronies."

Runs more than 1,100 miles

Dakota Access and pipeline supporters say the $3.7 billion pipeline project would be an economic boon.

The developer estimates the pipeline would bring $156 million in sales and income taxes to state and local governments and would add 8,000 to 12,000 construction jobs.

The pipeline would stretch 1,172 miles through four states -- from North Dakota into South Dakota, winding through Iowa and ending in southern Illinois -- moving 470,000 barrels of crude oil a day across the Midwest. It is completed, except for the contested portion under Lake Oahe.

Like Dakota Access, the Keystone XL Pipeline had been the subject of environmental concern from activists, residents and indigenous tribes who worried that the pipeline would pollute as many as 2,500 aquifers.

But pipeline supporters touted the jobs it would create and other economic benefits.

The $8 billion Keystone pipeline was proposed to stretch nearly 1,200 miles across six states, shuttling carbon-heavy petroleum from Canada to the Gulf Coast.

In November 2015, Obama nixed the proposed pipeline, virtually ending the fight over the project that had gone on for much of his presidency.

But Trump's executive actions on both pipelines signal how his administration will take a different approach to energy and environmental issues.