BISMARCK, N.D. (AP) — A group that has helped lead protests against the Dakota Access oil pipeline says it’s expecting hundreds of people to turn out across the country to protest the Army’s approval of the project.

The Army said Tuesday it will allow the pipeline to cross under a Missouri River reservoir in North Dakota, the last big chunk of construction for the $3.8 billion project to move North Dakota oil to Illinois.

Members of the Indigenous Environmental Network and Standing Rock Sioux are calling for protests nationwide. Events are scheduled in many cities, including New York, Washington, D.C., Seattle, Denver and San Francisco.

The Indigenous Environmental Network says opponents are ready to challenge the pipeline “in the courts and in the streets.”

Pipeline developer Energy Transfer Partners says it will be safe.