More than 400 demonstrators clashed with police on a bridge north of a protest encampment near the Standing Rock Sioux reservation in North Dakota on Sunday night. Protesters said they were trying to access what they described as sacred tribal lands, which are under the jurisdiction of the U.S. Army Corps of Engineers.
The protesters were stopped by a line of police officers, requested by the Corps to keep protesters off the land.
Deputies deployed tear gas and fired on protesters with a water cannon on the Backwater Bridge, according to a news release from the Morton County, N.D., Sheriff's Department on Sunday night.
The temperature dipped to 27 degrees in Cannon Ball, with a wind chill that hit 18 degrees.
The Sheriff's Department described the situation as a riot, and said protesters had attempted to outflank officers and set multiple fires on the bridge.
Protesters began camping on land sacred to the Standing Rock Sioux tribe in April. Protesters argue the land would be threatened by the 1,170-mile, four-state Dakota Access pipeline when it crosses a section of the Missouri River next to the reservation. The tribe has argued in court filings opposing the pipeline that its construction will damage sacred sites and put the tribe's water supply at risk.
Video livestreamed by protesters on Sunday showed large plumes of tear gas on the bridge, the same one where protesters burned two trucks on Oct. 27.
According to the Sheriff's Department, the clashes began about 6 p.m. when protesters attempted to move one of the burned trucks.
Protesters and police have engaged in direct standoffs multiple times in the last three months, most recently 10 days ago when 33 people were arrested after refusing to remove a roadblock from Highway 6, a major thoroughfare.