Victory for Native Americans and climate activists who had been protesting against the $3.8bn project.

The US Army Corps of Engineers has turned down a permit for a controversial pipeline project running through North Dakota, in a victory for Native Americans and climate activists who have protested against the project for several months.

The 1,885km Dakota Access Pipeline, owned by Texas-based Energy Transfer Partners LP, had been complete except for a segment planned to run under Lake Oahe, a reservoir formed by a dam on the Missouri River.

“The Army will not grant an easement to cross Lake Oahe at the proposed location based on the current record,” a statement from the US Army said.

The Standing Rock Sioux tribe, along with climate activists, have been protesting the $3.8bn project, saying it could contaminate the water supply and damage sacred tribal lands.

The protest has garnered support from thousands who have flocked to North Dakota to protest against the completion of the line.

“Today, the US Army Corps of Engineers announced that it will not be granting the easement to cross Lake Oahe for the proposed Dakota Access Pipeline,” said Standing Rock Chairman Dave Archambault II, in a statement.

“Instead, the Corps will be undertaking an environmental impact statement to look at possible alternative routes.”

But Energy Transfer Partners can still appeal the decision, according to a lawyer representing the tribe.

“They can sue, and the Trump administration can try to overturn [the decision],” Jan Hasselman, a staff lawyer for Earthjustice, told US media.

REPORTER’S NOTEBOOK: Dakota pipeline protesters dig in for winter

Energy Transfer Partners has already said that it was unwilling to reroute the project.

“The administration’s statement today that it would not at this time issue an ‘easement’ to Dakota Access Pipeline is a purely political action,” Energy Transfer Partners said in a press release on Sunday.

The company also stated that it is “fully committed to ensuring that this vital project is brought to completion and fully expect to complete construction of the pipeline without any additional rerouting in and around Lake Oahe.

“Nothing this administration has done today changes that in any way,” it added.

Protest organisers had for months argued that crossing the Missouri River adjacent to the Standing Rock Sioux Reservation presented a danger to their water source.

Protests grew over the months, with hundreds of veterans flocking to the camp in recent days to stand against what they say are aggressive tactics from law enforcement.

Earlier on Sunday, an organiser with Veterans Stand for Standing Rock said tribal elders had asked the military veterans not to have confrontations with law enforcement officials, adding the group is there to help out those who have dug in against the project.