WASHINGTON (Reuters) - A U.S. federal judge on Monday denied a request by Native American tribes seeking to halt construction of the final link in the Dakota Access Pipeline, the controversial project that has sparked months of protests by activists aimed at stopping the 1,170-mile line.

People protest under the statue of Lafayette against U.S. President Donald Trump's directive to permit the Dakota Access Pipeline during a demonstration at the White House in Washington, U.S., February 8, 2017. REUTERS/Joshua Roberts

At a hearing, Judge James Boasberg of the U.S. District Court in Washington, D.C., rejected the request from the Standing Rock Sioux and Cheyenne River Sioux tribes, who argued that the project would prevent them from practicing religious ceremonies at a lake they contend is surrounded by sacred ground.

With this decision, legal options for the tribes continue to narrow, as construction on the final uncompleted stretch is currently proceeding.

Last week, the U.S. Army Corps of Engineers granted a final easement to Energy Transfer Partners LP ETP.N, which is building the $3.8 billion pipeline (DAPL), after President Donald Trump issued an order to advance the project days after he took office in January.

Another hearing is scheduled for Feb. 27, as the tribes seek an injunction ordering the Army Corps to withdraw the easement.

Lawyers for the Cheyenne River Sioux and the Standing Rock Sioux wanted Judge Boasberg to block construction with a temporary restraining order on the grounds that the pipeline would obstruct the free exercise of their religious practices.

“We’re disappointed with today’s ruling denying a temporary restraining order against the Dakota Access Pipeline, but we are not surprised,” Chase Iron Eyes, a member of the Standing Rock Sioux tribe, said in a statement.

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The company needs to build a 1,100-foot (335 meter) connection in North Dakota under Lake Oahe, part of the Missouri River system, to complete the pipeline.

The line would run from oilfields in the Northern Plains of North Dakota to the Midwest, and then to refineries along the Gulf of Mexico, and could be operating by early May.

Judge Boasberg ordered Energy Transfer Partners to update the court on Monday and every week thereafter on when oil is expected to flow beneath Lake Oahe.

The company did not respond to requests for comment.

Iron Eyes said during an earlier conference call that the pipeline would also cause economic harm to Native Americans.

In his statement, he said the tribe was still seeking an injunction against the pipeline, which would also be heard in Boasberg’s court. They also are continuing to push for a full environmental impact statement that was ordered in the last days of the Obama Administration.

“We continue to believe that both the tribes and the public should have meaningful input and participation in that process,” he said.

Thousands of tribe members, environmentalists and others set up camps last year on Army Corps land in the North Dakota plains as protests intensified. In December, the Obama Administration denied the last permit needed by Energy Transfer Partners, but with Trump’s stated support of the pipeline that victory was short-lived for the tribes.

The Army Corps has said it would close remaining camps on federal lands along the Cannonball River in North Dakota after Feb. 22.

Tom Goldtooth, executive director of the Indigenous Environmental Network, one of the primary groups protesting the pipeline, said people would continue to leave the main camp. He said he expected more demonstrations around the country.

Only a few hundred protesters remained, and crews have been removing tipis and yurts. The Standing Rock tribe has asked protesters to leave.