The Army Corps of Engineers will not grant a key permit for the Dakota Access Pipeline to cross under the lake on the Standing Rock reservation in North Dakota, securing an enormous win for the Native American community and protesters who opposed the construction.

“Although we have had continuing discussion and exchanges of new information with the Standing Rock Sioux and Dakota Access, it’s clear that there’s more work to do,”Jo-Ellen Darcy, the Army’s assistant secretary for Civil Works, announced in a statement on Sunday afternoon. “The best way to complete that work responsibly and expeditiously is to explore alternate routes for the pipeline crossing.”

1,172-mile-long pipeline would have sent roughly 470,000 barrels of crude oil under the Missouri River per day. A leak or spill could have contaminated the Native American community’s drinking water supply.

Standing Rock Sioux Tribal chairman Dave Archambault II said that his community will be forever grateful to the Obama administration for its decision to pursue alternative routes for the project.

“We wholeheartedly support the decision of the administration,” he said in his statement, “and commend with the utmost gratitude the courage it took on the part of President Obama, the Army Corps, the Department of Justice, and the Department of the Interior to take steps to correct the course of history and to do the right thing.”

Protesters occupy Standing Rock reservation, North Dakota Show all 15 1 /15 Protesters occupy Standing Rock reservation, North Dakota Protesters occupy Standing Rock reservation, North Dakota A person pours a pepper spray antidote into a protester's eyes during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota Reuters Protesters occupy Standing Rock reservation, North Dakota People swim across a river to where the police officers are standing guard during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota Reuters Protesters occupy Standing Rock reservation, North Dakota A man holds up a ceremonial object while police officers look down from a hill during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters Protesters occupy Standing Rock reservation, North Dakota People protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota November Reuters Protesters occupy Standing Rock reservation, North Dakota Two people stand in the water of a river while police officers guard the shore during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota Reuters Protesters occupy Standing Rock reservation, North Dakota A man stands on a makeshift bridge over a river while police officers stand on the opposite shore during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters Protesters occupy Standing Rock reservation, North Dakota Police use pepper spray against protesters in a boat during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters Protesters occupy Standing Rock reservation, North Dakota Police use pepper spray against protesters in a boat during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters Protesters occupy Standing Rock reservation, North Dakota Police use pepper spray against protesters in a boat during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters Protesters occupy Standing Rock reservation, North Dakota Tonya Stands recovers after being pepper sprayed by police after swimming across a creek with other protesters hoping to build a new camp to block construction of the Dakota Access Pipeline, near Cannon Ball, Reuters Protesters occupy Standing Rock reservation, North Dakota Dakota Access Pipeline protesters stand in the foreground and in the waist-deep water of the Cantapeta Creek, northeast of the Oceti Sakowin Camp, near Cannon Ball, N.D., Wednesday, Nov. 2, 2016. Officers in riot gear clashed again Wednesday with protesters near the Dakota Access pipeline, hitting dozens with pepper spray as they waded through waist-deep water in an attempt to reach property owned by the pipeline's developer. Reuters Protesters occupy Standing Rock reservation, North Dakota Dakota Access Pipeline protesters stand in the foreground and in the waist-deep water of the Cantapeta Creek, northeast of the Oceti Sakowin Camp, near Cannon Ball, N.D., Wednesday, Nov. 2, 2016. Officers in riot gear clashed again Wednesday with protesters near the Dakota Access pipeline, hitting dozens with pepper spray as they waded through waist-deep water in an attempt to reach property owned by the pipeline's developer. Reuters Protesters occupy Standing Rock reservation, North Dakota People who were tear gassed return to the shore during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, Reuters Protesters occupy Standing Rock reservation, North Dakota People yell at police officers standing on the opposite shore of a river during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters Protesters occupy Standing Rock reservation, North Dakota Police use pepper spray against protesters in a boat during a protest against the building of a pipeline on the Standing Rock Indian Reservation near Cannonball, North Dakota, U.S Reuters

However, today’s announcement is not a complete victory for protesters. As the Obama administration’s days in office come to an end, it’s unclear if President-elect Donald Trump, who owns stock in the company spearheading the project, will continue supporting the project. In recent days, he’s claimed that his support has nothing to do with his monetary investment in the company.

The National Congress of American Indians immediately responded to the announcement by saying that the fight is far from over.

“This isn’t over, but it is enormously good news,” President Brian Cladoosby said in the statement. “All tribal peoples have prayed from the beginning for a peaceful solution, and this puts us back on track. From the start, the Standing Rock Sioux Tribe has asked for a full analysis to consider threats to the water and environment, and also the social and cultural impacts. Peace, prayer, and the water protectors have led to the right outcome.”

Over the weekend, thousands of veterans joined protesters who oppose the Dakota Access pipeline to build shelters in the frigid conditions and prevent clashes with local law enforcement in the area who have injured hundreds of people who oppose the $3.8 billion project.