Policemen gather at the site of one of the protests. (Screen shot via Unicorn Riot)

A peaceful prayer ceremony at a Dakota Access pipeline (DAPL) construction site was interrupted Wednesday by a highly militarized police raid in which 21 protesters were arrested.

The website Unicorn Riot, which has been covering the protests closely, described Wednesday’s events:

The caravan [of demonstrators] was followed by two helicopters and a circling airplane. Workers had left the area moments before the protectors arrived. After praying for nearly an hour, everyone gathered to caravan to a second site. … The water protectors went to a second site to pray. They prayed for 40 minutes and as they left the site, a large amount of police vehicles arrived and blockaded the only exit on the public road leading to the DAPL work site. Dozens of militarized police with shotguns appeared with a Bearcat armored vehicle as well as an MRAP [a Mine-Resistant Ambush Protected vehicle]. … After blockading the exit points, police vehicles sped across open fields towards the crowd of protectors as they left the site. Several arrests were made, as police brandished loaded shotguns, and assault rifles.

Images and video of the police raid were shared via social media:

Water Protectors gather to pray at #DakotaAccessPipeline construction site. Heliocopters swirl overhead. #NoDapl pic.twitter.com/BGUhb6Vo78 — Unicorn Riot (@UR_Ninja) September 28, 2016

Crop duster flies over spraying as people move back to their vechiles. #NoDAPL pic.twitter.com/xEuKu3A66k — Unicorn Riot (@UR_Ninja) September 28, 2016

Unicorn Riot also streamed live video of the police raid:

This new wave of state-sponsored aggression toward the DAPL demonstrators comes just one week after Standing Rock Sioux Chairman David Archambault II testified before the United Nations Human Rights Commission. “I am here because oil companies are causing the deliberate destruction of our sacred places and burials,” he said. “This pipeline threatens our communities, the river and the earth.” In a statement made after his testimony, Archambault noted that the months-long, peaceful protests have only “been met with violence.”

“Thousands have gathered peacefully in Standing Rock in solidarity against the pipeline,” he said. “And yet many water protectors have been threatened and even injured by the pipeline’s security officers.”

Several days after his U.N. testimony, The New York Times published an opinion piece by Archambault. In it, he explains the cultural importance of the land. He also critiques the politics governing this environmental issue. “Perhaps only in North Dakota, where oil tycoons wine and dine elected officials, and where the governor, Jack Dalrymple, serves as an adviser to the Trump campaign, would state and county governments act as the armed enforcement for corporate interests,” he writes. “In recent weeks, the state has militarized my reservation, with road blocks and license-plate checks, low-flying aircraft and racial profiling of Indians.”

After briefly outlining the historical pattern of conflict between Native Americans and the U.S. government, Archambault reinforces the peaceful message of his tribe. “As American citizens, we all have a responsibility to speak for a vision of the future that is safe and productive for our grandchildren,” he writes. “As our songs and prayers echo across the prairie, we need the public to see that in standing up for our rights, we do so on behalf of the millions of Americans who will be affected by this pipeline.”

The Morton County Sheriff’s Department notes that since Aug. 11, 95 people have been arrested “for illegal protest activity” in the area. Other outlets continue to assert that, despite the escalating reactions to the demonstrators, mainstream media continue to ignore the issue.