CANNON BALL, N.D. (AP) - Authorities have moved in to remove Dakota Access pipeline protesters camped on private land in the path of the pipeline in North Dakota.

The operation that commenced at midday involves dozens of officers in riot gear, some of them armed, along with trucks, police cars, military Humvees and buses. At least two helicopters and a fixed-wing airplane monitored the operation from the air.

Officials told protesters over a loudspeaker to move out.

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Protesters parked cars on the highway near the camp and slashed the vehicles' tires to try to slow the authorities. They also set a small fire at one of two blockades they set up on the highway.

The forcible removal began a day after protesters refused to leave voluntarily.

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