CANNON BALL, North Dakota - On the day when thousands of United States Military Veterans descended upon the Oceti Sakowin Camp in North Dakota, the U.S. Army Corps of Engineers announced Sunday afternoon that it will not approve an easement that would allow the proposed Dakota Access Pipeline to cross under Lake Oahe in North Dakota.

Jo-Ellen Darcy, Army's Assistant Secretary for Civil Works, said in a statement, she based her decision on a "need to explore alternate routes for the Dakota Access Pipeline crossing," and that tribal officials have expressed repeated concerns over the risk that a pipeline rupture or spill could pose to its water supply and treaty rights.

The proposed pipeline would have ran half a mile north of the Standing Rock Sioux Reservation. The Standing Rock Sioux and thousands of other American Indians have been protesting the pipeline for several months at the Oceti Sakowin Camp.

A few thousand veterans from all over the country have been arriving in North Dakota all weekend to show their support for the camp and to provide protection, veterans said. 

Although frequently called 'protesters' nationally, the Standing Rock Sioux people and their allies called themselves 'water protectors.'

Standing Rock Sioux Tribal Chairman Dave Archambault II thanked everyone who played a role in advocating for the cause. 

"Today, the U.S. Army Corps of Engineers announced that it will not be granting the easement to cross Lake Oahe for the proposed Dakota Access Pipeline. Instead, the Corps will be undertaking an environmental impact statement to look at possible alternative routes," Archambault said in a statement released by the tribe. "We wholeheartedly support the decision of the administration 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."

Oceti Sakowin Camp Headsmen Council issued a response to following the U.S. Army Corps of Engineers announcement.

"We are excited by the news that the easement is not going to be granted. We hope that in all future endeavors the United States government will honor its words and provide meaningful consultation with tribal nations regarding ancestral homelands. Our hearts are heavy for those who sacrificed themselves and endured a great difficulty in order to protect the water and land for our future generations," the council wrote in a statement issued via Facebook.

Archambault said he's stressed the significance of remaining peaceful at all times, and that the water protectors and the Standing Rock people can now look forward to returning to their homes. 

"Throughout this effort I have stressed the importance of acting at all times in a peaceful and prayerful manner – and that is how we will respond to this decision. With this decision we look forward to being able to return home and spend the winter with our families and loved ones, many of whom have sacrificed as well. We look forward to celebrating in wopila, in thanks, in the coming days," Archambault said. 

Though it is being viewed as a victory, many remain cautious as they proceed. 

"It is not a straight denial, but rather a major suspension on a decision pending a limited EIS," wrote Indigenous Environmental Network Organizer Dallas Goldtooth on his Facebook page. "The U.S. Army Corps will conduct a limited Environmental Impact Statement on the river crossing and explore possibilities for alternative routes. This is a win! A huge win!"

Darcy, with the Department of the Army, said  the consideration of alternative routes would be best accomplished through an Environmental Impact Statement with full public input and analysis.

"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," Darcy said. "The best way to complete that work responsibly and expeditiously is to explore alternate routes for the pipeline crossing." 

The Standing Rock tribe said it hopes that CEO of Energy Transfer Partners Kelcey Warren, Governor Jack Dalrymple and the incoming Trump administration respect this decision and understand the complex process that led us to this point. 

"When it comes to infrastructure development in Indian Country and with respect to treaty lands, we must strive to work together to reach decisions that reflect the multifaceted considerations of tribes," Archambault said. "Treaties are paramount law and must be respected, and we welcome dialogue on how to continue to honor that moving forward. We are not opposed to energy independence, economic development, or national security concerns but we must ensure that these decisions are made with the considerations of our Indigenous peoples."

The Standing Rock Sioux tribe also reached out to local North Dakota law enforcement in its statement. 

"To our local law enforcement, I hope that we can work together to heal our relationship as we all work to protect the lives and safety of our people. I recognize the extreme stress that the situation caused and look forward to a future that reflects more mutual understanding and respect," Archambault said. 

The Dakota Access Pipeline is an approximately 1,172 mile pipeline that would connect the Bakken and Three Forks oil production areas in North Dakota to an existing crude oil terminal near Pakota, Illinois. The pipeline is 30 inches in diameter and is projected to transport approximately 470,000 barrels of oil per day, with a capacity as high as 570,000 barrels. The current proposed pipeline route would cross Lake Oahe, an Army Corps of Engineers project on the Missouri River.