At least seven more people have been arrested during protests near Cannon Ball.
Tensions rose during the protests last week as construction began on the Dakota Access pipeline in the area.
The pipeline route goes just north of the Standing Rock Reservation and under the Missouri River.
Protesters have been stationed at a site near the route most of the summer.
Construction began in the area last Wednesday.
Protests began to escalate Thursday evening.
Morton County Sheriff’s deputies arrested 11 people that day.
Monday morning a cement barrier was in place to separate protesters from workers.
KX Crews saw two people arrested after they tried to cross the barriers.
The North Dakota Highway Patrol sent out a press release Monday morning encouraging drivers to avoid Highway 1806 because there could be delays.
Highway 1806 runs south from Mandan to South Dakota.
It passes by the area where protesters gathered.