CANNON BALL, N.D. - Standing Rock Sioux Chairman Dave Archambault is renewing a call for Dakota Access oil pipeline opponents to leave a camp in southern North Dakota.

A blizzard hitting the region has brought driving snow, wind gusts up to 55 mph and wind chills as low as minus 25 degrees. A blizzard warning is calling for at least one to two more inches of snow and continued white-out conditions. A number of highways and interstates have been closed across central and western North Dakota.

Archambault says there's no reason for people in the camp to put their lives at risk. And he says emergency shelters on the nearby reservation are already full.

Some people at the camp spent the night at shelters that Morton County set up in Flasher and Mandan. Others stayed at the tribe's casino, about 4 miles from the camp.

Pipeline opponents have vowed to maintain the camp through the winter. They believe the pipeline threatens the tribe's drinking water and cultural sites.

Morton County set up shelters at school facilities in Bismarck and Flasher. Spokeswoman Maxine Herr says about 30 people took advantage of the shelters.

Pipeline opponent Michelle Cook calls the brutal weather just "a test of everybody's resolve," and that the camp will prevail through the winter.