-- About 76 "rogue" protesters were arrested Wednesday near the Dakota Access Pipeline in North Dakota, authorities said.
The group was given a period to begin dismantling the camp and leave, but members did not show signs of vacating, despite "multiple warnings," and said they wouldn't leave, the sheriff's department said. The officers decided to "enforce the law and evict" the group, the department said.
"After repeated warnings to vacate a camp being illegally set up on private property in southern Morton County, south of Backwater Bridge, approximately 76 members of a rogue group of protesters were arrested by law enforcement officials today," the Morton County Sheriff's Department said in a press release.
The camp was cleared by about 4 p.m. local time, authorities said.
Demonstrators from one of the previously established protest sites attempted to set up a camp across the road from their existing one because of concerns about spring flooding, one of the group leaders told ABC News on Wednesday. The leader said they believed they had the rights to use the land, although it is now private property, under a 19th century treaty.
The arrests were "relatively peaceful," the leader said, adding that while national guardsmen were on the scene to assist the sheriff's office, they did not participate in the arrests.
Thousands of Native Americans, environmental activists and their allies have camped out near the Standing Rock reservation for months to protest the Dakota Access Pipeline, in one of the largest Native American demonstrations in decades. The protesters, who call themselves water protectors, argue that the pipeline will threaten the reservation's water supply and traverse sacred sites.
The Standing Rock Sioux Tribe has been at the forefront of the prolonged protests against the pipeline project. The 1,172-mile, four-state crude oil pipeline is almost finished, except for a section under Lake Oahe just upstream of the Standing Rock reservation that has been the focus of the protests.
In July the tribe sued to block the project, claiming it was never meaningfully consulted before construction began. The tribe cites an 1851 treaty that it says designated the land in question for Native American tribes. That lawsuit is pending, and the Army Corps and the pipeline company argued in court papers that they followed a standard review process.
Kelcy Warren, the CEO of Energy Transfer Partners, the Texas-based firm that's building the pipeline, said that "concerns about the pipeline's impact on local water supply are unfounded" and "multiple archaeological studies conducted with state historic preservation offices found no sacred items along the route."
ABC News' Evan Simon contributed to this report.