The Dakota Access Pipeline protests continued Sunday. This time, authorities say someone used a drone to attack a helicopter that was monitoring the area.
The Morton County Sheriff's Department in North Dakota says the drone flew at the helicopter "in a threatening manner."
According to the department, a sheriff on board said the helicopter's passengers were "in fear of their lives" when "the drone came after us."
Around 11 a.m., officials say the drone was flying over officials in violation of Federal Aviation Administration rules. So law enforcement used "less-than-lethal" ammunition to shoot and damage the drone until its operator landed it.
This isn't the first time drones have been used during pipeline protests. The sheriff's department says two drone operators have previously been charged for crimes involving illegal use of unmanned aircraft systems.
You can read a summary of the FAA's small unmanned aircraft rule here.
Authorities say protesters also fired arrows at a helicopter, created an illegal road block on Highway 1806 and "illegally occupied private property" by bringing tents and teepees to a construction site.
As of Sunday morning, 200 protesters and eight horses had entered the private property east of Highway 1806.
Saturday, a group of about 300 activists marched onto a private construction site and 83 were arrested.
According to the Washington Times, officers used pepper spray against activists Saturday. Then at one point, a protester grabbed a can and sprayed an officer in the face.