Hunters aboard a helicopter took aim at wolves that have been killing sheep in Stevens County in northeast Washington.

The Spokesman-Review reports state officials have OK'd the hunt for a portion of a wolf pack that's killed at least 22 sheep this month.

The announcement comes after the state authorized a rancher to shoot the same wolves approaching his flock of 1,800 sheep.

But the state Fish and Wildlife Department says efforts to deter the pack have failed. So agency Director Phil Anderson says he authorized the killing of four wolves from the pack, which is estimated at up to 12 members.

By 4 p.m. Saturday, the newspaper reported that no wolves had been killed.

Conservation groups are opposed, saying killing wolves is not an effective way to protect livestock.