ILLINGS, Mont. — A new federal rule would allow state game agencies to kill endangered gray wolves that prey on wildlife in the Northern Rockies.

An estimated 1,500 Wolves in Idaho, Wyoming and Montana are scheduled to come off the endangered species list in coming weeks, which would allow public hunting of the predators for the first time in decades.

Thursday's federal rule is a separate action that would give the three states more latitude to kill wolves even if the delisting is delayed.

State wildlife agents would be empowered to kill packs of wolves if they could prove the animals were having a "major impact" on big game herds such as elk, deer and moose.

Environmental groups have pledged to challenge the rule and the planned delisting in court.