JANESVILLE, Wis. -

More Wisconsin deputies headed northwest to help law enforcement in North Dakota, the Rock County Sheriff's Office said.

Sheriff Robert Spoden said in a news release that it sent five Rock County deputies Sunday to assist the Morton County Sheriff's Office in Mandoon, North Dakota.

Law enforcement in North Dakota are managing crowds that are protesting the Dakota Access Pipeline project.

The Rock County deputies join 10 Dane County deputies who also deployed to assist in North Dakota. St. Croix County, Marathon County and Wisconsin State Patrol troopers have also sent officers to help in North Dakota.

North Dakota law enforcement have been working to manage the protests since August. Members of the Standing Rock Sioux Tribe and environmentalists have been protesting the pipeline, which will carry about 450,000 barrels of oil per day from North Dakota's Bakken oil fields to Illinois. Protestors said the pipeline passes over sacred grounds and will be a threat to the environment.

The deputies are expected to return Oct. 18, according to a news release.