The confrontations between police and Dakota Access pipeline protesters grew even more violent in recent days, including what protesters describe as a concussion grenade thrown by police that may cost one protester her arm.

Sophia Wilansky, 21, faces potential amputation of her left arm after the latest incident early Monday morning near Cannon Ball, N.D.  

Pipeline opponents say they were trying to clear burnt-out vehicles that were part of a police blockade on Highway 1806 when law enforcement officials led by the Morton County Sheriff’s department used rubber bullets, tear gas, concussion grenades and water cannons in an attempt to repel them. Hundreds of protesters stood before the police line throughout the night in sub-freezing temperatures after the confrontation began.

Michael Knudsen, a medic with Standing Rock Medic and Healer Council, said he was at a loss to describe Sunday’s confrontation with police.

“I think of Birmingham, [Alabama], I think of Wounded Knee, it felt like low-grade war,” he said. “If we hadn’t been there on Sunday night, people would have probably died. The use of water canons for 8 hours on hundreds and hundreds of demonstrators in 22 degrees is enough to kill someone.”

A spokesperson for Morton County Sheriff denied the use of concussion grenades or anything else that would have caused such a powerful blast.

Grenade pieces were removed from Wilansky’s arm in surgery and will be saved for evidence, said the Standing Rock Medic & Healer Council, a group that provided medical assistance to protesters during Sunday night’s standoff.

Wilansky, who had traveled from New York to support the protest, was handing out water to unarmed pipeline protesters early Monday morning near the police line when the explosion occurred, according to the medic group.

“At around 4:30 am after the police hit the bridge with water cannons and rubber bullets and pepper spray they lobbed a number of concussion grenades which are not supposed to be thrown at people directly at protesters or ‘protectors’ as they want to be called,” Sophia’s father, attorney Wayne Wilansky, said in a statement.

“A grenade exploded right as it hit Sophia in the left forearm taking most of the undersurface of her left arm with it. Both her radial and ulnar artery were completely destroyed. All of the muscle and soft tissue between her elbow and wrist were blown away.”

Wilansky said his daughter’s injury was not an accident but “an intentional act of throwing it directly at her.”

The Morton County Sheriff’s department did not respond to requests for comment.

“There was an explosion in the protester area that we don’t know where it came from but it wasn’t law enforcement,” Morton County Sheriff Kyle Kirchmeier said in a press briefing on Monday.  Kirchmeier also said they used a fire hose, not a “water cannon.”  

Knudsen, the medic, said he was in a triage site away from the front line where he helped people who had been maced or exposed to tear gas, coordinated evacuations, assessed rubber bullet wounds and provided hypothermia care.

He said his group treated at least 300 people, 26 of whom were transported to medical facilities. The group used all of the approximately 1,000 emergency blankets  they had on hand.

Wilansky’s injury appeared to be the most serious.

“Sophia will have surgery again tomorrow as bit by bit they try to rebuild a somewhat functioning arm and hand,” Wilansky’s father said. “She will be, every day for the foreseeable future, fearful of losing her arm and hand. There are no words to describe the pain of watching my daughter cry and say she was sorry for the pain she caused me and my wife.”

A fund set up to help cover Wilansky’s medical costs has already raised more than $210,000, with the environmental advocacy group Climate Hawks Vote promising to partially match the donations.

ICN’s Zahra Hirji contributed reporting for this story.