FARGO, N.D.  — Backers of a Red River diversion project around the Fargo-Moorhead area say a Minnesota agency’s refusal to issue a work permit won’t be a factor for many years and construction should go forward on the North Dakota side.

Diversion opponents say they might ask a judge to halt the start of construction.

The U.S. Army Corps of Engineers has set aside $5 million for construction of a gated inlet structure, which is the first phase of the $2.2 billion project. The Fargo-Moorhead Diversion Authority is hoping to start on the inlet in the next few months.

Attorneys on both sides filed court documents this week updating their positions on a lawsuit filed by upstream residents asking for a cheaper project that won’t flood farmland. Gerald Von Korff, lawyer for diversion opponents, said the authority should get all necessary permits — Including those from the state of Minnesota — before starting construction.

Diversion authority lawyer Robert Cattanach countered in a strongly worded document that the decision by the Minnesota Department of Natural Resources to deny a permit for an upstream dam contradicts the agency’s finding that emergency flood measures are not a reasonable alternative.