CANNON BALL, N.D. (Reuters) – U.S. military veterans were set to arrive at a camp to join thousands of activists braving snow and freezing temperatures to protest a pipeline project near a Native American reservation in North Dakota.

Protesters have spent months rallying against plans to route the $3.8 billion Dakota Access Pipeline beneath a lake near the Standing Rock Sioux reservation, saying it poses a threat to water resources and sacred Native American sites.

State officials had issued an order on Monday for activists to vacate the Oceti Sakowin camp, located on U.S. Army Corps of Engineers land near Cannon Ball, North Dakota, citing harsh weather conditions. Officials said on Wednesday they will not actively enforce that order.

The Standing Rock Sioux, in a statement on Wednesday, scoffed at the state order, noting that because “the Governor of North Dakota and Sheriff of Morton County are relative newcomers” to the land, “it is understandable they would be concerned about severe winter weather.”

They said the camp has adequate shelter to handle the cold weather, adding that the Great Sioux Nation has survived “in this region for millennia without the concerns of state or county governments.”

The temperature in Cannon Ball is expected to fall to 6 degrees Fahrenheit (-2 Celsius) by the middle of next week, according to Weather.com forecasts.

The 1,172-mile (1,885 km) pipeline project, owned by Texas-based Energy Transfer Partners LP, is mostly complete, except for a segment planned to run under Lake Oahe, a reservoir formed by a dam on the Missouri River.

Veterans Stand for Standing Rock, a contingent of more than 2,000 U.S. military veterans, intends to reach North Dakota by this weekend and form a human wall in front of police, protest organizers said on a Facebook page.

Protesters, who refer to themselves as “water protectors,” have been gearing up for the winter while they await the Army Corps decision on whether to allow Energy Transfer Partners to tunnel under the river. That decision has been delayed twice by the Army Corps.

(Reporting by Terray Sylvester; Editing by Meredith Mazzilli)