Peacefully throwing things at police and setting fires.
Via ABC:
Police arrested 16 people at a protest against the Dakota Access Pipeline in North Dakota today as officers attempted to disperse the crowd, authorities said.
Officers also used pepper spray against protesters who police said were throwing things at them and refusing to comply with law enforcement’s orders.
Three protesters had used devises to attach themselves to objects, presumably so they could not be moved from the site by officers, a press release from the Morton County public information officer said.
“The protesters are not being peaceful or prayerful,” Cass County Sheriff Paul Laney said in the press release. “Law enforcement has been very methodical in moving ahead slowly as to not escalate the situation. However, the protesters are using very dangerous means to slow us down. Their aggressive tactics include using horses, fire and trying to flank us with horses and people.”
An estimated 250 protesters against the pipeline are at one site and about 80 others at another location nearby, the press release said.