FARGO, N.D. (AP) — Supporters of a Red River diversion channel around Fargo and Moorhead, Minnesota, say a lawsuit filed by upstream opponents should be thrown out and the project should move forward.

The Fargo-Moorhead Diversion Authority plans to begin work soon on the $2.1 billion project. A lawsuit filed by upstream residents whose land would be flooded in times of high water says construction should not be able to start until it receives permits from the state of Minnesota.

The diversion authority says that any work that would impact Minnesota will be done by the U.S. Army Corps of Engineers and a federal judge has ruled that the corps is exempt from Minnesota environmental law.

Upstream opponents on Wednesday asked a judge to halt the project until the permits are issued.

(© Copyright 2016 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)