Democratic Sen. Heidi Heitkamp (N.D.) released a statement Monday criticizing the violent protests in her state that broke out the prior day over the Dakota Access Pipeline.
In her statement, Heitkamp insisted that safety remains "of the utmost importance, and it's imperative that it remain the top priority for all of those involved in these protests."
She also suggested that the violent nature of the recent protests should not be tolerated.
"Any protesters should be able to exercise their First Amendment right lawfully and peacefully, but many of the actions we have seen over the past several weeks are not those of lawful protesters and they pose serious safety concerns to other protesters," Heitkamp said.
The protests, which have been ongoing for months, took a downturn on Sunday night when hundreds of demonstrators tried to start fires around the protest site, which prompted North Dakota law enforcement to disperse the crowd with water cannons, the Washington Post reported.
As temperatures in Cannon Ball, N.D., dropped into the 20s, police in riot gear sprayed activists with a hose mounted atop an armored vehicle and formed a line to prevent them from advancing up the road, according to the Bismarck Tribune. Protesters also reported being pelted with rubber bullets, tear gas, and concussion grenades during the standoff, which lasted until late Sunday night.
A grainy Facebook Live video from the scene shows throngs of people gathered around the Backwater Bridge on Highway 1806, with flood lights shining down on the grass and road below and a haze of smoke and water vapor rising near police vehicles.
The clashes began around 6 p.m., when protesters tried to remove burned out trucks that had been blocking the bridge since authorities and activists faced off there in late October. Police have since set up wire and concrete barriers on the bridge, which is about a mile south of where the pipeline developer plans to drill.
Heitkamp also said in her statement that she has been in contact with White House officials and the Army Corps of Engineers to push for a quicker easement decision from the courts about the pipeline's construction under Lake Oahe in southern North Dakota.
The Dakota Access Pipeline would carry crude oil from North Dakota through South Dakota and Iowa to Illinois, where it would connect with existing pipelines to carry the oil to the Gulf Coast.
Proponents of the project argue it will pour millions of dollars into local economies and provide thousands of jobs. Native American and environmental activists have opposed the pipeline's construction, arguing it would harm the environment and the wellbeing of local tribes.