The standoff between authorities and Dakota Access Pipeline protesters turned violent Sunday night, with police at one point using a water cannon in freezing conditions.
The Bismarck Tribune reports that pipeline protesters tried to remove burned out vehicles that are blocking the Backwater Bridge on Highway 1806, which has been closed since Oct. 27 when law enforcement pushed protesters back to the main camps near the Standing Rock Indian Reservation.
Protesters argue that closing the bridge, which police say was done for safety reasons, blocks emergency service acess to the reservation and prevents them accessing construction sites to the north.
Water cannons were used to repel protesters on Sunday night, the newspaper notes.
The Morton County Sheriff's Office referred the incident as an "ongoing riot," estimating that 400 protesters were on the bridge and were "attempting to breach the bridge to go north on Highway 1806."
It says protesters started "a dozen fires" near the bridge.
According to the Washington Post, the sheriff's department said protesters were "very aggressive" and were attempting to "flank and attack the law enforcement line."
You can find some background on why the protest is happening here.
Water cannon, tear gas, rubber bullets used
The clashes started around 6 p.m. about a mile south of where the pipeline is intended to go.
The use of water cannons was condemned by physicians and tribal healers with the Standing Rock Medic and Healing Council on a night that temperatures dropped below freezing, CNN reports.
They called for "the immediate cessation of use of water cannons" amid concerns of hypothermia in the cold weather, calling the actions of police a "potentially lethal use of these confrontational methods against people peacefully assembled."
In a statement from the Indigenous Environmental Network, Honor the Earth and Sacred Stone Camp, protest leaders said police also used tear gas, stinger grenades and rubber bullets during the clashes.
They claimed that "multiple people were unconscious" after being shot with rubber bullets, and "one elder went into cardiac arrest at the frontlines," but medics were able to resuscitate him. The injured were taken back to the nearby Cannon Ball gym, which has become a makeshift medical shelter.
Tara Houska, of Honor the Earth, said: "For weeks, the main highway to the Standing Rock Sioux Reservation has been cut off, with no movement by the state to address a public safety risk.
"Attempting to clear the road was met with police spraying people with water cannons in 26 degree weather – that’s deadly force, it’s freezing outside."