STANDING ROCK SIOUX RESERVATION, N.D. (AP) -

A federal judge is set to deliver a key ruling on the four-state Dakota Access Pipeline that has drawn thousands of protesters to a construction site in North Dakota, some coming form as far as New York and Alaska.

U.S. District Judge James Boasberg says he'll rule by the end of Friday on the Standing Rock Sioux tribes' request to block the $3.8 billion project, which will carry oil from North Dakota to Illinois.

The tribe argues the project threatens water supplies and has already disrupted sacred sites. The developer, Dallas-based Energy Transfer Partners says modern technology allows quick detection of leaks. Pipeline supporters also say it would cut the amount of oil that travels by train.

Early Friday, the Great Plains Tribal Chairman's Association has asked U.S. Attorney General, Loretta Lynch to send federal monitors to the site of a large pipeline protest in North Dakota.

President, John Yellow Bird Steele sent a letter to Lynch on Thursday saying protesters have been attacked by private security with guard dogs and that radical profiling is occurring. Authorities say some protesters are armed with hatchets and knives, and Saturday's protest injured guards and dogs.

During the early afternoon on Friday, an attorney says the Yankton Sioux Tribe's lawsuit over the Dakota Access pipeline is not expected to have any immediate bearing, and she wouldn't say whether the tribe would ask the federal court to temporarily block construction of it.

The lawsuit from the South Dakota tribe was filed Thursday and is separate from the one filed by the Standing Rock Sioux on which a federal judge is expected to rule Friday.

Tribal attorney Jennifer Baker says the lawsuit will take time, but that the Yankton Sioux wants to stand beside Standing Rock, Cheyenne River, and other tribes because they share rights to the water and the land.

The complaint says the pipeline route passes through the tribe's territory, aboriginal title lands, and areas of cultural and spiritual importance.