According to various reports from Twitter users as well as at least one livestream, protests at the Standing Rock Reservation turned violent tonight, as police forces employed tear gas and/or mace and water cannons to deter further protest at a blockade point.
One Facebook user, Kevin Gilbertt, is livestream now and reported at approximately 10:15 p.m. EST that tear gas was being fired "indiscriminately" in the crowds of people while airplanes are reportedly flying overhead with their lights off. At one point, people could be heard screaming "medic" in the background. Watch that livestream here.
This story is developing, and we will update as more information becomes available.