Officers in riot gear cleared protesters away from a site where an oil pipeline is under construction near Cannon Ball, North Dakota, Thursday.
The sheriff's office in Morton County says 141 protesters were arrested at the site where demonstrators opposed to the project had blockaded a highway through land owned by the company building the Dakota Access Pipeline.
The sheriff's office described it as a "very active and tense evening," saying protesters threw rocks, molotov cocktails, logs, bottles and other debris at officers when they tried to remove them.
And while they were arresting one woman, she pulled out a gun and fired three rounds at the police line.
Leading up to the arrests
Hundreds of law enforcement officers advanced on the group late Thursday morning, with Sheriff Kyle Kirchmeier saying in a statement: "We cannot have protesters blocking county roads, blocking state highways, or trespassing on private property."
Some of the protesters set fires as officers approached. For a time during the afternoon, deputies were focused on getting the demonstrators to clear away so fires could be put out. They used a device sometimes called a sound cannon that sends out a high-pitched noise, ABC News reports.
By nightfall, Kirchmeier said protesters were no longer on the site owned by Energy Transfer Partners, the company building the pipeline.
Many of them retreated to a nearby area where anti-pipeline demonstrators have been camping out for months, the Guardian reports.
The sheriff's office first said there were no injuries but in a follow-up statement said they were investigating reports that a private citizen who had been forced off a highway by protesters was shot in the hand.
What's the protest about?
The Dakota Access Pipeline is being built to deliver crude oil more than 1,100 miles from the Bakken region of North Dakota to Illinois, where it can be sent through existing lines to refineries on the Gulf Coast.
Its route runs within a mile of the Standing Rock Sioux Reservation near Cannon Ball. The tribe argues the pipeline threatens its water supply and the construction is violating sacred sites. They've been joined by supporters from around the country.
A court turned down a request by critics of the line to put the project on hold, but federal agencies did agree to pause construction on part of the route that runs through government-owned land.
The Morton County Sheriff's Office has a timeline of events leading up to Thursday's arrests. View it here.