Tires burn as armed soldiers and law enforcement officers stand in formation on Thursday, Oct. 27, 2016, to force Dakota Access pipeline protesters off private land where they had camped to block construction. The pipeline is to carry oil from western North Dakota through South Dakota and Iowa to an existing pipeline in Patoka, Ill. (Mike McCleary/The Bismarck Tribune via AP)
Tires burn as armed soldiers and law enforcement officers stand in formation on Thursday, Oct. 27, 2016, to force Dakota Access pipeline protesters off private land where they had camped to block construction. The pipeline is to carry oil from western North Dakota through South Dakota and Iowa to an existing pipeline in Patoka, Ill. (Mike McCleary/The Bismarck Tribune via AP) Credit: Mike McCleary

Law enforcement officers dressed in riot gear and firing bean bags and pepper spray evicted protesters Thursday from private land in the path of the Dakota Access oil pipeline, dramatically escalating a months-long dispute over Native American rights and the projectโ€™s environmental impact.

In an operation that took nearly six hours, hundreds of armed state and local police and National Guard โ€“ some on foot and others in trucks, military Humvees and buses โ€“ pushed past burning barricades to slowly envelop the camp.

No serious injuries were reported, though one man was hurt in the leg and received treatment from a medic.

More than a dozen protesters who refused to leave were arrested and taken to the Morton County Jail, Sheriff Kyle Kirchmeier said.

Among those arrested was a woman who pulled out a .38-caliber pistol and fired three times at officers, narrowly missing a sheriffโ€™s deputy, according State Emergency Services spokeswoman Cecily Fong. Officers did not return fire, she said.

Kirchmeier said that the camp had been cleared by nightfall although police were still dealing with protesters on the perimeter. Though officials earlier said they planned to turn the site over to private security, Kirchmeier said police would stay for now.

โ€œWeโ€™re not leaving the area,โ€ he said. โ€œWe are just going to make sure that we maintain a presence in the area so the roadway stays open, and to keep individuals from camping on private land.โ€

Opponents of the pipeline over the weekend set up camp on private land owned by Texas-based Energy Transfer Partners, which is working to complete the 1,200-mile pipeline to carry oil from western North Dakota to Illinois. The route skirts the Standing Rock Reservation and the tribe says it could endanger water supplies and disturb cultural sites.

The tribe has gone to court to challenge the U.S. Army Corps of Engineersโ€™ decision granting permits at more than 200 water crossings. A federal judge in September denied their request to block construction, but three federal agencies stepped in to order construction to halt on Corps-owned land around Lake Oahe.