11/26/2016 06:34 EST | Updated 11/27/2017 00:12 EST

Republican senator: Pipeline protesters should leave camp

CANNON BALL, N.D. — North Dakota U.S. Sen. John Hoeven says opponents of the Dakota Access oil pipeline should respect the law and leave the protest area.

The Republican made the statement after the U.S. Army Corps of Engineers sent a letter Friday to Standing Rock Sioux tribal chairman Dave Archambault that said the federal land about 50 miles south of Bismarck on which the vast majority of protesters have gathered at the Oceti Sakowin camp will close Dec. 5.

Archambault says the letter cites the oncoming winter and confrontations between protesters and police. He also says, "our resolve to protect our water is stronger than ever."

Hoeven is calling for the Obama administration to approve the easement for the pipeline, saying the situation needs to be resolved.