BISMARCK, N.D. — A federal judge has ordered the Army Corps of Engineers to turn over more documents that four Native American tribes say could bolster their lawsuit seeking to shut down the Dakota Access pipeline in North Dakota.

U.S. District Judge James Boasberg directed the federal agency to give up the documents by Wednesday, the Bismarck Tribune reported.

The Standing Rock, Cheyenne River, Yankton and Oglala Sioux tribes accused the Corps in February of withholding dozens of documents that they say could show how the pipeline may threaten the Lake Oahe reservoir on the Missouri River, which serves as their water source.

Fears of an oil spill into the river sparked massive protests in 2016 and 2017, drawing thousands of pipeline opponents to North Dakota.

Federal officials had turned over some documents, but said requests for dozens more were vague or too broad.

The tribes accused the Corps of producing a "fragmented and incomplete record" to justify its approval of the $3.8 million pipeline that began carrying oil from North Dakota to Illinois in June 2017. Last week, the pipeline's operator, Texas-based Energy Transfer Partners, announced plans to double its capacity.

It's unclear how useful the documents will be to the tribal case.

Boasberg gave the tribes an Aug. 16 deadline to submit their final arguments. The case won't be resolved for several months after the filing.

The Standing Rock Sioux tribe plans to request a full environmental impact study of the pipeline and for the pipeline's operations to be shuttered during the review, according to Jan Hasselman, an attorney for environmental law organization Earthjustice.

"In the meantime, we're gearing up for an election," Hasselman said. "A new administration could well undo the Trump (administration) permits."