A crowd celebrates at the Oceti Sakowin camp after it was announced that the U.S. Army Corps of Engineers won't grant easement for the Dakota Access oil pipeline in Cannon Ball, N.D., Sunday, Dec. 4, 2016. (AP Photo/David Goldman)
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A crowd celebrates at the Oceti Sakowin camp after it was announced that the U.S. Army Corps of Engineers won't grant easement for the Dakota Access oil pipeline in Cannon Ball, N.D., Sunday, Dec. 4, 2016. (AP Photo/David Goldman)
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CANNON BALL, ND - DECEMBER 05:  Military veterans are briefed on cold-weather safety issues and their overall role at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois.  (Photo by Scott Olson/Getty Images)
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CANNON BALL, ND - DECEMBER 05: Military veterans are briefed on cold-weather safety issues and their overall role at Oceti Sakowin Camp on the edge of the Standing Rock Sioux Reservation on December 5, 2016 outside Cannon Ball, North Dakota. Over the weekend a large group of military veterans joined native Americans and activists from around the country who have been at the camp for several months trying to halt the construction of the Dakota Access Pipeline. Yesterday the US Army Corps of Engineers announced that it will not grant an easement for the pipeline to cross under a lake on the Sioux Tribes Standing Rock reservation. The proposed 1,172-mile-long pipeline would transport oil from the North Dakota Bakken region through South Dakota, Iowa and into Illinois. (Photo by Scott Olson/Getty Images)
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Story highlights

The Army Corps of Engineers says the Dakota Access Pipeline must be rerouted

The Standing Rock Sioux tribe opposes the pipeline because its federal reservation lies nearby

(CNN) —  

Celebrations, tears of joy, chanting and drumming rang out among thousands of protesters after the US Army announced it will not – for now – allow developers to build a portion of the Dakota Access Pipeline under Lake Oahe here.

For months, members of the Sioux tribe and their supporters have camped out, fighting the pipeline they say could be hazardous and damage the water supply of their reservation nearby.

“People have said that this is a make it or a break it, and I guess we made it,” Chief Arvol Looking Horse, Keeper of the White Buffalo Calf Pipe, announced to a cheering crowd of protesters.

Tribal leaders worry the decision to change direction may not be permanent, especially with the incoming Trump administration, as well backers of the pipeline seeking to push the project ahead.

Grassroots activists, who have turned the protest site into a mini-city, prepared to withstand freezing temperatures during what was expected to be an even lengthier standoff, were cautious about the scope and durability of their victory.

“I’m really happy that I’m here to witness it and celebrate with a lot of my elders and the youth, but I think that we also need to keep in mind that we need to be ready to keep going,” said protester Morning Star Angeline Chippewa-Freeland.

“We are asking our supporters to keep up the pressure, because while President Obama has granted us a victory today, that victory isn’t guaranteed in the next administration,” Dallas Goldtooth, lead organizer for the Indigenous Environmental Network, said in a statement. “More threats are likely in the year to come, and we cannot stop until this pipeline is completely and utterly defeated, and our water and climate are safe.”

Army: Look for alternative routes

The Army Corps of Engineers said it will not grant a permit to allow the proposed pipeline to cross under the lake. Officials said after discussion with the tribe and Dakota Access it became clear that more work had to be done on the project.

“The best way to complete that work responsibly and expeditiously is to explore alternate routes for the pipeline crossing,” The corps’ assistant secretary for civil works, Jo-Ellen Darcy, said in a statement.

The decision comes three weeks after her office announced it was delaying the decision after protests from the Standing Rock Sioux tribe and its supporters.

Darcy said the consideration of alternative routes would be best accomplished through an environmental impact statement with full public input and analysis, delivering both an immediate reprieve and political statement that could aid in future showdowns with President-elect Donald Trump’s incoming administration.

Pipeline supporters speak out

Energy Transfer Partners and Sunoco Logistics Partners said Sunday night that they believe the Army’s decision was a politically motivated move triggered by the White House.

As far as they’re concerned, the White House’s directive does not change past court decisions to green light the project.

“Nothing this Administration has done today changes that in any way,” the company said in a statement.

North Dakota Sen. John Hoeven, a Republican, said last week after a meeting with the transition team that Trump supported completing the 1,172-mile long proposed pipeline, that would transport 470,000 barrels of oil a day across four states. A spokeswoman for Trump did not immediately respond to a request for comment on Sunday’s decision.

House Speaker Paul Ryan tweeted his criticism of the Army’s announcement, calling the intervention “big-government decision-making at its worst.”

North Dakota’s sole member in the House of Representatives, Rep. Kevin Cramer, a Republican, slammed Obama.

North Dakota’s sole member in the House of Representatives, Rep. Kevin Cramer, a Republican, pledged to fight on and slammed President Obama.

“It was becoming increasingly clear he was punting this issue down the road,” Cramer wrote in a statement. “Today’s unfortunate decision sends a very chilling signal to others who want to build infrastructure in this country.”

Opponents ready for next fight

The Army’s decision may be useful in a court challenge, according to Jan Hasselman, an Earthjustice staff attorney representing the Standing Rock Sioux tribe.

“If the incoming administration tries to undo this and jam the pipeline through despite the need for an analysis of alternatives, we will certainly be prepared to challenge that in court,” he said. “It’s not so simple for one government administration to simply reverse the decisions of the former one.”

May Boeve, the executive director leading environmental action group 350.org, celebrated the decision but also sounded a warning against any future plans to reverse it.

Sen. Bernie Sanders, who actively opposed the pipeline, praised the administration’s decision.

“I appreciate very much President Obama listening to the Native American people and millions of others who believe this pipeline should not be built,” Sanders, a 2016 Democratic presidential candidate, said in a statement. “In the year 2016, we should not continue to trample on Native American sovereignty. We should not endanger the water supply of millions of people.”

May Boeve, the executive director leading environmental action group 350.org, celebrated the decision but also sounded a warning against any future plans to reverse it.

“The fight against Dakota Access has fired up a resistance movement that is ready to take on any fossil fuel project the Trump administration tries to approve,” she said. “On Dakota Access and every other pipeline: If he tries to build it, we will come.”

From threat of removal to celebration

Earlier this week, North Dakota Gov. Jack Dalrymple ordered the protesters to leave the campsite by Monday, citing the harsh weather conditions as a reason why they needed to decamp. The US Army Corps of Engineers had warned that come Monday, activists who refused to leave the campsite could be arrested, then backtracked, saying the agency had no plans to forcibly remove those who stay.

Instead of backing away, the protesters came out in full force and showed no signs of backing down, even inviting over 2,000 veterans to join their already robust presence. Now with a victory for the Sioux tribe and their supporters, Standing Rock has become a protest symbol.

CNN’s Sara Sidner reported from Cannon Ball, North Dakota; Caroline Kenny and Gregory Krieg reported and wrote from Washington, DC. CNN’s Barbara Starr, Susanna Capelouto, Kevin Bohn and Max Blau contributed to this report.