There have also been reports that authorities are using beanbag guns. Protesters could be heard calling for a medic in the live stream.

A spokesperson for North Dakota's emergency services confirmed 16 arrests to the Guardian. The escalation began this morning, when authorities started trying to remove protesters they said were trespassing on private property near Highway 1806 in Morton County, the sheriff's department said in a news release.

Protesters lit a barricade on fire first on Highway 1806, then on a bridge on County Road 134. The Morton County sheriff's department confirmed in a Facebook post that they have a Long Range Acoustic Device for crowd control, which is essentially a high-powered speaker that can play sounds loud enough to damage hearing.