Eight arrests were made at the Dakota Access Pipeline south of Mandan in Morton County.
Two men had bound themselves to construction equipment about 20 miles west of the main protest site.
It took authorities several hours to cut one of the men free.
Construction was temporarily halted.
A woman was also arrested after she was repeatedly asked to get off of the equipment.
Five others were arrested for disorderly conduct.
Construction has been stopped for days near the main protest near the Standing Rock Sioux reservation.