Houston: The company behind the Dakota Access pipeline has bought more than 6000 acres of land adjacent to the line's route in North Dakota, parcels the Standing Rock Sioux tribe says contain historical artifacts, according to media reports on Saturday.

The land deal is a blow to the Sioux and other protesters who claim the pipeline would damage ancient burial sites and pose an environmental risk to the tribe's water supply. Federal oil pipeline regulators do not have authority over private land and cannot block construction on it.

North Dakota's Forum News Service first reported the sale on Friday.

Dakota Access is controlled by Energy Transfer Partners, which did not immediately respond to requests for comment.

When fully connected to existing lines, the 1770km Dakota Access pipeline would be the first to carry crude oil from the Bakken shale, a vast oil formation in North Dakota, Montana and parts of Canada, directly to the US Gulf.

According to a deed filed with officials in Morton County, North Dakota, David and Brenda Meyer sold 20 parcels of land totaling more than 6000 acres to Dakota Access this week. The price was not disclosed, Forum said.

The land includes a plot along the pipeline route where protesters and the company have clashed in recent weeks.

The Meyers had already signed easements for the pipeline. The sale gives Dakota Access effective control of one of the more controversial parts of the route.

The Meyers had paid the federal government for cattle grazing rights on a plot of land currently occupied by the Sioux and other pipeline protesters, Forum said.

The US Justice Department and other federal agencies intervened to delay construction on the pipeline earlier this month in what industry and labor representatives called an "unprecedented" move after a judge blocked a lawsuit from the Sioux to halt the project.

Reuters