CANNON BALL, N.D. (AP) — The Cheyenne River Sioux tribe has joined the Standing Rock Sioux in asking a federal judge to revoke permission for the Dakota Access pipeline to be built under the Missouri River in North Dakota.

The tribes say the $3.8 billion oil pipeline threatens their drinking water, cultural sites and ability to practice their religion, which depends on pure water. Developer Energy Transfer Partners rejects those claims, and expects to finish work under the river quickly, perhaps in two weeks.

Earlier this month, the Standing Rock Sioux asked U.S. District Judge James Boasberg to overturn permission for the river crossing that the pro-energy Trump administration granted to ETP. The Cheyenne River tribe filed a similar request on Wednesday.

The Cheyenne River Sioux requested an injunction to stop the construction earlier this month.

ETP hasn’t yet responded to the motions.