The U.S. Army Corps of Engineers rejected an easement for the Dakota Access Pipeline Sunday, calling instead for alternatives for the pipeline to be considered.

  • Dakota Access Pipeline will not be built under Lake Oahe
  • Standing Rock Sioux have said a rupture could damage their water supply
  • Protests over project have gone on for months

The move is a victory for pipeline protesters and the Standing Rock Sioux, who have demonstrated against the pipeline project for months.

In a statement Sunday, the Corps said the pipeline would not be built under Lake Oahe, a Missouri River reservoir that provides water for the Standing Rock Sioux.

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

The tribe has expressed repeated concerns that a pipeline rupture or spill would threaten the tribe's water supply and cultural sites. While the pipeline was not supposed to cross onto tribe property, the Standing Rock says construction would disturb tribal burial sites on that land.

The Corps said alternative routes would be best reached through an Environmental Impact Statement with full public input and analysis.

Tense and sometimes violent protesters have gone on for months in the Cannon Ball area. Last month authorities sprayed water on protesters in freezing temperatures. Human rights groups have condemned tactics used by law enforcement.

The federal government has ordered people to leave the main protester encampment by Monday. 

Demonstrators have said they are prepared to stay. Authorities say they won't forcibly remove the protesters.

Meanwhile a group of hundreds of veterans arrived at the protest site on Sunday to stand with the Standing Rock protesters. The Veterans for Standing Rock group will join the camp on federal land.

The Dakota Access Pipeline is a 1,172-mile pipeline that connects the Bakken and Three Forks oil production areas in North Dakota with a crude oil terminal near Pakota, Illinois. The pipeline is projected to transport about 370,000 barrels of oil per day.

Information from the Associated Press was used in this report.