Police arrested a group of 141 demonstrators in North Dakota after a standoff that ended early Friday morning, according to Reuters. The group, made up of members of the Standing Rock Sioux Tribe and other environmental activits, were protesting the construction of the Dakota Access Pipeline.
According to the Morton County Sheriff’s Department, police wore riot gear and used pepper spray and armored vehicles to disperse the crowd of roughly 330 protesters, who also resorted to violence. The site of the protest is in the path of the $3.8 billion pipeline, Reuters reports.
The Dakota Access Pipeline is being built by a group of companies led by Energy Transfer Partners LP and is set to be 1,172 miles. Reuters reports that its completion would offer the “fastest and most direct route” to bring oil from North Dakota to refineries on the Gulf Coast.Â
 The Standing Rock Sioux Tribe believe that the pipeline will threaten water supply and sacred tribal sites.
Protests have been going on for several months now, with dozens of people being arrested. Celebrities such as Shailene Woodley and Mark Ruffalo have spoken out against the pipeline, and Woodley was even arrested. Of the 141 arrested on Friday, charges included “conspiracy to endanger by fire or explosion, engaging in a riot and maintaining a public nuisance,” according to Reuters.