Four Blackfoot men pleaded not guilty to causing last summer's North Fork fire, which charred 120,000 acres in the Targhee National Forest and Yellowstone National Park.

Roy Momerak, Herbert V. Butler, Nathan Wright and Leland J. Owens entered their pleas Thursday before U.S. Magistrate Craig Jorgensen in Pocatello.No trial date was immediately set and all four were released on their own recognizance.

U.S. Attorney Maurice Ellsworth filed a notice of violation against the men last month in Boise. It accuses them of knowingly throwing or placing a lit cigarette in dry grass or timber in the Targhee National Forest last July 22.

The fire threatened the Old Faithful area, Canyon Village and the town of West Yellowstone, Mont.