BISMARCK, N.D. (AP) – North Dakota has sued the federal government to recover the $38 million the state spent policing protests against the Dakota Access oil pipeline.

Attorney General Wayne Stenehjem (STEHN’-juhm) says he filed the lawsuit Thursday against the Army Corps of Engineers. He says the agency didn’t respond to an administrative claim he filed one year ago.

The agency did not immediately return calls seeking comment.

Stenehjem says the Corps allowed protesters to illegally camp without a permit on federal land along the Missouri River in southern North Dakota and failed to maintain law and order.

The Corps has said protesters weren’t evicted due to free speech reasons.

The pipeline carries oil from North Dakota through South Dakota and Iowa to a shipping point in Illinois. It began moving oil in 2017.