CANNON BALL, N.D. (AP) — Protesters trying to block the Dakota Access oil pipeline urged unity on Saturday as they prayed together near burned-out construction vehicles that served as a barricade between activists and law enforcement officers.

Following two days of confrontations with law enforcement, at least 150 people prayed near the barricade in chilly, cloudy weather in southern North Dakota. Women in Native American regalia participated in the prayer, which stressed the need for protesters to work together. Opponents of the project have been camped near the pipeline route for months in an effort to stop construction.

“Our camp needs to continue to be peaceful and prayerful,” Caroline High Elk, who has stayed at the encampment for brief periods eight times over the past few months, said Saturday. “But there are some who are been aggressive and energetic in a way because they want to be the fearless warrior.”

The $3.8 billion pipeline was designed to carry oil 1,200 miles from western North Dakota through South Dakota and Iowa to a shipping point at Patoka, Illinois. But the Standing Rock Sioux tribe objects to the project, saying it passes so close to its reservation that any leak could pollute the local water supply. They also said the pipeline could disturb sacred cultural sites.

The protest escalated last weekend, when demonstrators set up camp on private land along the pipeline’s path that had recently been acquired by Energy Transfer Partners. On Thursday, more than 140 people were arrested as law enforcement — bolstered by reinforcements from several states — slowly moved in and cleared them off the private land.

Then on Friday, dozens of people moved behind the burned vehicles and heavy plywood along a highway, facing concrete barriers, military vehicles and police in riot gear. Don Cuny, the security leader for activists at the encampment, said Saturday that standoff “does not represent” the ongoing protest.

Cuny noted that disagreements have surfaced about how to demonstrate, but he said any people involved in the protest who instigate trouble would be kicked out of the encampment. Stressing unity, he said: “More numbers make you more powerful.”

“Enough is enough. Natives have been ignored throughout history,” said Holly Doll, a tribal member who was among more than 60 protesters at another rally Saturday at the state Capitol in Bismarck. “Our voices may be small, but we are strong. This is about looking ahead for future generations and protecting our water.”

The camp cleared on Thursday was located just to the north of the more permanent, larger encampment, which has been allowed on federally owned land and is a main staging area for hundreds of protesters from around the country including Native Americans, environmentalists and some celebrities.

Sandra Chasing Hawk, 37, a Standing Rock Sioux member who has been at the protest camp for months, said joining the movement has been a religious experience for her.

“Our elders are keeping us together. They are bringing unity,” she said.

A federal judge in September denied the tribe’s request to block construction after it argued that the Army Corps of Engineers improperly issued permits.

North Dakota officials have said no culturally significant sites have been found in the area. But on the day the judge ruled, three federal agencies stepped in to order construction to halt on Army Corps-owned land around Lake Oahe, a wide spot of the Missouri River, while the Corps reviewed its decision.

Construction has been allowed to continue on private land owned by the developer, with a goal of completion by the end of the year.

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Associated Press reporters James MacPherson in Cannon Ball, and John Mone and Blake Nicholson in Bismarck contributed to this report.