Work resumed Thursday on the controversial Dakota Access oil pipeline in the north central U.S., while an Indian tribe went to court again in a last-minute effort to stop the project.

The U.S. Army Corps of Engineers had given the go-ahead Wednesday for the work to continue. President Donald Trump ordered the project completed after former President Barack Obama had put it on hold.

The company building the pipeline, Energy Transfer Partners, started drilling under Lake Oahe in North Dakota immediately after getting word from the army. It says it expects to have the project finished and oil flowing in 83 days.

The Standing Rock Sioux Indian tribe filed another court motion to try to stop the project. It says the corps broke its word to have a further environmental study.

Tribe leaders contend the pipeline is too close to their water supply and sacred land. They say an oil spill or a rupture in the pipe would be a disaster for millions of people.

They accuse the Trump administration of showing contempt for the environment and putting oil company greed ahead of their treaty and water rights.

Pipeline supporters contend the pipe is safe and that transporting oil underground poses much less risk to the environment than using trains and trucks.

Native Americans and their supporters have held a nearly nonstop protest near the lake, which sometimes has erupted in violence.