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The Standing Rock Sioux Tribe has asked the U.S. Department of Justice to immediately intervene in the escalating situation between protesters and law enforcement over construction of the Dakota Access Pipeline, the tribe's chairman told NBC News on Sunday night.

"The DOJ should be enlisted and expected to investigate the overwhelming reports and videos demonstrating clear strong-arm tactics, abuses and unlawful arrests by law enforcement," Chairman Dave Archambault II told NBC News.

The tribe's request comes after a weekend in which the months-long protest entered a new and more chaotic phase. On Saturday, 127 protesters were arrested on suspicion of criminal trespassing on private property, according to new figures released Sunday by the Morton County Sheriff's Office.

Members of the Standing Rock Sioux Tribe have been protesting construction of a $3.7-billion pipeline, which would transport 470,000 barrels of oil each day across four states. They see the pipeline as an environmental and cultural threat to their land, arguing an oil spill would permanently contaminate the reservation's water supply and that construction of the pipeline would destroy lands where many of their ancestors are buried.

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The pipeline would come within a half mile of the Standing Rock Sioux reservation, which straddles the North and South Dakota border.

Protests continued Sunday when another group of 400 opponents set up roadblocks less than three miles east of the main Oketi Sakowin Camp in Cannon Ball, North Dakota. The group strung barbed wires and placed tree stumps and other large-scale items across State Highway 1806, the area's main thoroughfare.

The protesters set up the blockade to stop access to a critical construction site where work is slated to begin soon, Nick Tilsen, a protester, told NBC News. The blockade was still in place late Sunday night.

Tilsen said the blockade enabled more than 100 protesters to occupy private land at the site to prevent any construction.

"We re-claimed Indian land today," said Tilsen, an Oglala Sioux activist. "The tribes asserted sovereignty by using eminent domain and the protectors moved in to set up camp in the path of the pipeline."

Authorities also fired upon a protester's drone Sunday, which the sheriff's office said was flying directly above deputies in violation of Federal Aviation Administration rules. Tilsen said the group dispatched the drone to record any possible altercation between sheriff's deputies and protesters.

The contested site is a staging area crews would use to drill beneath the Missouri River. That phase of the project has so far been blocked by the Obama administration, pending a federal environmental review expected to be released after the Nov. 8 presidential election.

Energy Transfer Partners, the Dallas-based company funding the $3.7 billion project, could not be immediately reached for comment.

In a statement, Morton County Sheriff Kyle Kirchmeier called Sunday's protest "intentional, planned, coordinated and outright unlawful."

"Individuals trespassing on private property can’t claim eminent domain to justify their criminal actions," said Kirchmeier.