Women hold a demonstration on Backwater Bridge during a protest against plans to pass the Dakota Access pipeline near the Standing Rock Indian Reservation, near Cannon Ball, North Dakota, U.S. Thomson Reuters

(Reuters) - U.S. authorities said on Sunday they had no plans to forcibly remove activists protesting plans to run an oil pipeline beneath a lake near the Standing Rock Sioux reservation in North Dakota, despite telling them to leave by early December.

The U.S. Army Corps of Engineers, which manages the federal land where the main camp protesting the Dakota Access pipeline is located, said last week it would close public access to the area north of the Cannonball River on Dec. 5

On Sunday, the agency said in a statement that it had "no plans for forcible removal" of protesters. The statement said anyone who remained would be considered unauthorized and could be subject to various citations. It also said emergency services might not be adequately provided to the area.

"The Army Corps of Engineers is seeking a peaceful and orderly transition to a safer location," the statement said. "This will reduce the risk of harm to people in the encampments caused (by) the harsh North Dakota winter conditions."

A representative for the agency could not be immediately reached on Sunday to provide further clarification on its plans.

Organizers told a news conference on Saturday at the main protest site where about 5,000 people are camped that they had no intention of moving.

There are smaller camps on land not subject to the planned restrictions, including an area south of the Cannonball River where the Corps said it was establishing a free-speech zone.

Police confront protesters with a rubber bullet gun during a protest against plans to pass the Dakota Access pipeline near the Standing Rock Indian Reservation, near Cannon Ball, North Dakota, U.S. November 20, 2016. Stephanie Keith/REUTERS

Demonstrators have protested for months against the $3.8 billion Dakota Access Pipeline, owned by Energy Transfer Partners LP, saying it poses a threat to water resources and sacred Native American sites.

The companies say the pipeline would carry Bakken shale oil more cheaply and safely from North Dakota to Illinois en route to U.S. Gulf Coast refineries.

The 1,172-mile (1,885-km) project is mostly complete except for the segment planned to run under Lake Oahe, less than half a mile (0.8 km) north of Standing Rock.

The Obama administration in September postponed final approval of a permit required to allow tunneling beneath the lake, a move intended to give federal officials more time to consult with tribal leaders. The delay also led to escalating tensions over the project.

Last weekend, police used water hoses in subfreezing weather in an attempt to disperse about 400 activists near the proposed tunnel excavation site.

(Reporting by Curtis Skinner in San Francisco; Editing by Peter Cooneyand Peter Cooney)