MANDAN, N.D./WASHINGTON -- About 40 protesters against the Dakota Access oil pipeline were arrested on Friday, Nov. 11, in rural North Dakota as the U.S. Army Corps of Engineers said it would soon clarify its plans for the controversial project near sacred tribal lands.

U.S. Army Corps of Engineers spokeswoman Amy Gaskill said it would issue a decision on its next steps within a few days though it would perhaps not be a final decision.

It was unclear whether it would resolve the question of whether the line can be built under Lake Oahe, where construction had stopped in September.

Police again confronted about 100 protesters at a construction site on the pipeline, which has drawn steady opposition from Native American and environmental activists since the summer.

At least 39 protesters were arrested on Friday at the construction site, and deputies took pictures of vandalized equipment, which had wires cut and was spray-painted, Morton County Sheriff's Department spokeswoman Donnell Preskey said.

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A spokesperson for Energy Transfer Partners, which owns the line, confirmed two to three pieces of equipment had been damaged, but the extent was not known.

Smoke was seen billowing from a large excavation machine near a site off Route 6 in rural North Dakota, and protesters had also climbed into other equipment, according to a Reuters witness. Two workers were seen leaving the scene.

Completion of the $3.7 billion Dakota Access Pipeline, set to run 1,172 miles from North Dakota to Illinois, was delayed in September so federal authorities could re-examine permits required by the Army Corps of Engineers.

Plans called for the pipeline to pass under Lake Oahe, a federally owned water source, and to skirt the Standing Rock Sioux Reservation by about a half-mile. Most of the construction has been completed, save for this area under the lake.

The Standing Rock tribe and environmental activists said the project would threaten water supplies and sacred Native American sites and ultimately contribute to climate change. Protests have at times turned violent, as security dogs attacked activists during the summer and more recently as protesters have burned vehicles and equipment.

"The tribe continues to ask water protectors to remain peaceful and prayerful," said Standing Rock Sioux spokeswoman Chelsea Hawkins on Friday.

The Obama administration requested a voluntary halt to construction within 20 miles of the lake on each side.

Energy Transfer Partners, which owns the line, continued to build to the edge of the federal land where the lake is located.

The company earlier this week said it was "mobilizing" drilling equipment to prepare to tunnel under the lake. That has angered protesters, who planned more protests in coming days.

An ETP spokeswoman said, "Construction is actually complete in North Dakota, except for the bore under the lake, so there is nothing for them to stop."

Pipeline supporters say the project offers the fastest and most direct route for bringing Bakken shale oil from North Dakota to U.S. Gulf Coast refineries and would be safer than transporting the oil by road or rail.