WASHINGTON (REUTERS) - The US Army Corps of Engineers said on Wednesday (Feb 1) it has taken initial steps to review requests to approve the final permit to finish the Dakota Access pipeline, the focus of protests for months.

The move does not mean the government has granted right of way for the pipeline to build its last remaining stretch under the Missouri River near Cannon Ball, North Dakota, according to the Army Corps of Engineers.

On Tuesday (Jan 31), two US lawmakers from North Dakota said they had been told by Army officials that the project would be completed.

Energy Transfer Partners LP's Dakota Access pipeline stretches for 1,885 km from North Dakota's oil-producing Bakken region to Patoka, Illinois.

A coalition of Native American groups and environmentalists have argued that the US$3.8 billion (S$5.4 billion) oil project would damage sacred lands and that any leaks could pollute the water supply of the Standing Rock Sioux tribe.

Proponents believe the project is necessary to transport US oil safely and that it would create jobs.

The proposed stretch of pipeline at issue runs adjacent to the Standing Rock Sioux Reservation in southern North Dakota.

"The Assistant Secretary for the Army Civil Works will make a decision on the pipeline once a full review and analysis is completed in accordance with the directive," the Corps said in a statement.

The tribe had successfully won delays from the Obama administration for further environmental review, but last week President Donald Trump signed an executive order telling the Corps of Engineers to expedite review of the project.

Standing Rock Sioux Chairman Dave Archambault II last week said he has requested a meeting with Trump, but has not received a response.

US Senator John Hoeven of North Dakota said in a statement on Tuesday that Acting Secretary of the Army Robert Speer had told him and Vice President Mike Pence that Speer directed the Corps to proceed with the easement.

US Representative Kevin Cramer also said he had been informed of the directive.

However, the Army's statement on Wednesday said that the steps for review "do not mean the easement has been approved."

Several groups opposing the project, including the Standing Rock Sioux, said they would fight the granting of an easement in court. They said on Tuesday that Hoeven and Cramer were jumping the gun, and that an environmental study under way must be completed before the permit can be granted.

A spokesman for Hoeven, Don Canton, said Speer told the senator that the Army Corps was doing its due diligence in acting on Trump's memo from last week, and that Hoeven had not discussed the environmental study with the Corps.

Standing Rock representatives were not immediately available for comment on Wednesday.

In a statement posted on their website, the Sacred Stone camp asked protesters - who had recently cleared out - to return to their encampment so that they could stage another demonstration. That camp is located on Sioux land in Sioux County; it is not the site of the bulk of protests, which are in Morton County on federal land.

The main protest camp, known as Oceti Sakowin, had been the staging ground for numerous protests, some of which led to violent clashes between law enforcement and activists. The camp is in the process of being broken down, because it is located on a flood plain, and when it floods, any remaining structures could foul the Missouri River, the water source for the Standing Rock tribe.