Authorities began arresting people at a Dakota Access Pipeline protest site in Morton County, North Dakota today, according to the Associated Press and the Guardian. Protesters report being pepper sprayed by authorities on a live stream hosted by Cempoalli Twenny on his Facebook page. 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.

The protest is against the $3.7 billion Dakota Access Pipeline intended to carry crude oil from oil fields in North Dakota more than 1,100 miles to a refinery in northern Illinois. But the pipeline, approved by the Army Corps of Engineers, crosses the water source for the reservation of the Standing Rock Sioux Tribe as well as sites of cultural significance, the tribe says. People have been protesting the pipeline and its route since April. The Standing Rock Sioux Tribe sued the Army Corps of Engineers for not having been consulted on the route, and in September construction on one section was temporarily halted.