BILLINGS, Mont. (AP) — A ban on fishing, boating and other activities on Montana's Yellowstone River could last for months after an invasive parasite killed thousands of fish.

The closure includes a 183-mile stretch of the river and hundreds of miles of tributaries. State wildlife officials said Friday that the order will be lifted only after river conditions improve and fish stop dying.

Montana Fish, Wildlife and Parks spokeswoman Andrea Jones says that could take months. She says biologists will monitor conditions and the Yellowstone will open as soon as it's feasible.

State officials also retracted earlier statements that fish had been killed in Yellowstone National Park.

Fisheries biologist Scott Opitz says dead fish have been found up to the park's northern border but there are no confirmed deaths inside the park.