Construction of the last phase of the controversial Dakota Access Pipeline alongside a Native American reservation could begin as early as next week after a federal judge declined to block the work.

U.S. Judge James Boasberg of the U.S. District Court for the District of Columbia refused Tuesday to order the U.S. Corps of Engineers to prevent completion of the pipeline, according to the Reuters international news agency. The Dakota pipeline is designed to link shale oil production from the Northern Plains with existing pipelines in the Midwest.

Tribes go to court

A group of Native American tribes had sued for an injunction to prevent completion of the $3.8 billion line being built by Energy Transfer Partners, which is intended to pass beneath Lake Oahe in north dakota. Tribes contend the land is sacred to them, and any disturbance along the pipeline route could imperil their freshwater supply, Reuters said.

But Judge Boasberg said the Corps' permit allowing ETP to complete the pipeline had been properly issued. The judge also found that religious objections filed by the Standing Rock Sioux and Cheyenne River Sioux tribes had been raised too late in the more than 2-year-old proceeding.

'Simply unacceptable'

Chase Iron Eyes, an attorney for the Lakota People's Law Project, called the decision "simply unacceptable" and vowed to continue the dispute through other legal means.

Iron Eyes said the pipeline threatened water used by the Lakota nation and 17 million other people downstream from the pipeline. The Obama administration appeared to side with the tribes in December, but President Trump reinstated the construction schedule for the 1,170-mile pipeline in a Jan. 24 executive order.

Partners predict March

ETP spokeswoman Lisa Dillinger said the partners were pleased by the decision and ready to complete "the final piece of construction." She said oil could begin flowing under the Missouri River as soon as the middle of March.

Public opposition to the pipeline drew thousands to North Dakota last year to protest both the construction and the use of force against Native Americans who had erected a protest camp nearby.

Standing Rock Sioux chairman Dave Archambault II said his tribe would continue to fight the pipeline legally, including its contention that the Army Corps was required to complete a complex environmental impact report before further construction could be authorized. "The fight against the pipeline has changed, but it continues with as much strength as ever," Archambault told Reuters.