CANNON BALL, N.D.  — Protesters celebrated a major victory in their push to reroute the Dakota Access oil pipeline away from a tribal water source but pledged to remain camped on federal land in North Dakota anyway, despite Monday’s government deadline to leave.

Hundreds of people at the Oceti Sakowin, or Seven Council Fires, encampment cheered and chanted “mni wichoni” — “water is life” in Lakota Sioux — after the Army Corps of Engineers refused Sunday to grant the company permission to extend the pipeline beneath a Missouri River reservoir.

The Standing Rock Sioux tribe and its supporters argue that extending the project beneath Lake Oahe would threaten the tribe’s water source and cultural sites. The segment is the last major sticking point for the four-state, $3.8 billion project.

“The whole world is watching,” said Miles Allard, a member of the Standing Rock Sioux. “I’m telling all our people to stand up and not to leave until this is over.”

Despite the deadline, authorities say they won’t forcibly remove the protesters.

The company constructing the pipeline, Dallas-based Energy Transfer Partners, released a statement Sunday night slamming the Army Corps’ decision as politically motivated and alleging that President Barack Obama’s administration was determined to delay the matter until he leaves office.

“The White House’s directive today to the Corps for further delay is just the latest in a series of overt and transparent political actions by an administration which has abandoned the rule of law in favor of currying favor with a narrow and extreme political constituency,” the company said.

President-elect Donald Trump, a pipeline supporter, will take office in January, although it wasn’t immediately clear what steps his administration would be able to take to reverse the Army Corps’ latest decision or how quickly that could happen.

That uncertainty, Allard said, is part of the reason the protesters won’t leave.

“We don’t know what Trump is going to do,” Allard said.