BISMARCK, N.D. (AP) – An appeals court ruled Tuesday that a federal judge in North Dakota was correct in not barring police from using harsh methods against Dakota Access pipeline protesters.

There have been no protests since February, but the decision will allow a lawsuit to proceed in which pipeline opponents allege they were subjected to police brutality and their civil rights were violated.

The plaintiffs sued last November seeking to stop police from using tactics against protesters such as chemical agents and water cannons. U.S. District Judge Daniel Hovland refused the request and they appealed, putting on hold the rest of their lawsuit, which seeks unspecified damages for alleged police brutality and rights violations.

The protesters' attorney, Rachel Lederman, said her clients look forward to proceeding with those claims.

"We are determined to keep fighting for justice and we are optimistic that when we are able to present all the evidence, the district court judge and jury will determine that law enforcement's use of force was illegal," she said.

Lederman said she also believes the plaintiffs' case has been bolstered by developments since it was put on hold. Documents leaked to an online magazine in May show that TigerSwan, a private security company hired by Texas-based pipeline developer Energy Transfer Partners, used military-style counter-terrorism measures, had a close working relationship with public law enforcement and used propaganda.

Lederman said she hopes Hovland "will see that he has been misinformed about the nature of that (anti-pipeline) movement due to the efforts of these hired mercenaries, and will be able to take a fresh view of the evidence as the case moves forward."

TigerSwan has maintained that its efforts were aimed at creating a safe working environment and that it is the victim of a smear campaign.

Law enforcement – who allege that protesters made threats against officers and public officials, including the governor – asked Hovland in February to dismiss the lawsuit, saying police are entitled to immunity and protesters had failed to present any plausible claims that their rights were violated.

Attorneys from Bakke Grinolds Wiederholt, a firm representing law officers, said Tuesday they were pleased that Hovland will now be able to rule on their motion.

Hovland indicated in February that he didn't think protesters were likely to succeed on the merits of their claims.

The pipeline began moving oil from North Dakota to Illinois in June following months of delays caused by legal battles and more than half a year of protests in North Dakota that resulted in 761 arrests.

Opponents, including four Native American tribes, fear a leak could cause catastrophic environmental harm. The developer says its pipeline is safe.

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