As a federal court issues a decision regarding whether construction of a disputed pipeline can go forward, Amnesty International USA has sent a delegation of human rights observers to monitor the response of law enforcement to protests by Indigenous communities in North Dakota.

Thousands of people have gathered in recent weeks at the construction site of the Dakota Access Pipeline at the border of North and South Dakota, close to the Standing Rock Sioux Reservation. State law enforcement has removed state-owned water tanks that have served as the main supply of drinking water for the encampment, citing public safety concerns. 29 people have been arrested in the past two weeks.

AIUSA sent a letter today to the North Dakota Highway Patrol and the Morton County Sheriff Department notifying them of the delegation and outlining how authorities are required to act in accordance with international human rights standards and the U.S. Constitution during the policing of protests.

“It is the legitimate right of people to peacefully express their opinion,” the letter reads. “Public assemblies should not be considered as the ‘enemy.’ The command hierarchy must convey a clear message to law enforcement officials that their task is to facilitate and not to restrict a peaceful public assembly.“

Amnesty International has history of monitoring protests and police conduct to ensure adherence to international standards for human rights. In the United States, AIUSA has deployed delegations of observers to Ferguson, MO, and Baltimore, MD, to monitor protests in the wake of police killings, as well as to Cleveland and Philadelphia to monitor the protests outside the Republican and Democratic National Conventions earlier this year.

AIUSA’s letters to authorities in North Dakota make clear: