A US judge has denied a request to halt construction on a controversial oil pipeline in North Dakota.
The Dakota Access Pipeline is opposed by over 200 Native American tribes who fear its impact on waterways.
The $3.7bn (2.8bn) project will pass through four states, close to lands that are sacred to members of the Standing Rock Sioux Tribe.
But moments after the ruling the US government urged construction to stop temporarily at one particular site.
The Department of Justice called upon Texas-based Energy Transfer Partners to voluntarily halt construction temporarily within 20 miles of Lake Oahe, which is considered sacred to the regional native tribes.
Immediate reaction among the protesters camped in North Dakota was confusion.
“The tribes’ attempts to stop construction have been denied,” the Red Warrior Camp said in a Facebook statement, immediately after the judge’s ruling.
“Stay peaceful without backing down” they advised.
Judge James Boasberg had ruled that the US Army Corp of Engineers “likely” complied with federal law when they issued construction permits to Texas-based Energy Transfer Partners, who are constructing the pipeline.
Crude oil from the Bakken shale will be shipped to oil refineries on the US Gulf Coast.
Environmental and local activists believe that the transporting of up to 570,000 barrels of crude oil a day will imperil local waterways.
Proponents of the 1,879 km-pipeline’s construction believe it to be a safer method of transporting oil than the current methods being used, which is by rail and road.
In a joint statement with the DoJ, the US Army department – which issued the building permits – announced they were suspending construction in one key location.
“Construction of the pipeline on Army Corps land bordering or under Lake Oahe will not go forward at this time”, the Department of the Army announced in a joint statement with two other federal agencies.
A press conference is scheduled by the protesters later on Friday in Bismarck, North Dakota.
Ahead of Friday’s ruling, Dave Archambault II, chairman of the Standing Rock Sioux Tribe, called upon followers to “continue to be united and peaceful in our opposition to the pipeline”.
“Our ultimate goal is permanent protection of our sacred sites and our water,” Mr Archambault II said.
“We must continue to have faith and believe in the strength of our prayers and not do anything in violence. We must believe in the creator and good things will come.”