OLYMPIA — State officials approved the killing of a portion of a wolf pack in northeast Washington, sending hunters aboard a helicopter during the weekend to take aim at the wolves.

Officials from the state Department of Fish and Wildlife approved the killings for the Huckleberry Pack in Stevens County after 22 sheep were killed this month. But a conservation group argues the state did not exhaust non-lethal methods before ordering the hunt.

The hunt’s announcement comes after the state authorized a rancher to shoot the same wolves approaching his flock of 1,800 sheep. The state Fish and Wildlife Department said efforts to deter the pack have failed, The Spokesman-Review reported.

In an effort to break the predation cycle, agency Director Phil Anderson said he authorized on Saturday the killing of four wolves from the pack, which is estimated at up to 12 members. Officials will later evaluate whether that is enough lethal force to end the sheep attacks.

Gunners in a helicopter began flying over the area near Hunters on Saturday. A wolf was spotted, but officials said no wolves were killed Saturday. A male wolf is wearing a radio collar that researchers attached to monitor the pack.

“As of Friday, we had confirmed that 17 sheep had been killed by wolves in five separate incidents, and we continue to find more dead and wounded sheep from the flock,” said Bruce Botka, agency spokesman.

Botka said the situation meets the state’s conditions for lethal removal of wolves, which are protected in eastern Washington by state endangered species laws. The pack is one of about a dozen wolf packs confirmed in eastern Washington.

“There have been repeated, documented wolf kills; non-lethal methods have not stopped the predation; the attacks are likely to continue, and the livestock owner has not done anything to attract the wolves,” he said.

The Huckleberry Pack, named for the nearby Huckleberry Mountains, was documented as a pack in 2012. The pack had not been associated with attacks on livestock until this month, officials said

“It’s unconscionable that a public agency would take action to kill an endangered species without notifying the public. These wolves belong to the public and decisions about whether they live or die ought to be made in the clear light of day,” said Amaroq Weiss, West Coast wolf organizer with the Center for Biological Diversity, in a statement.

Weiss’ group argues the state did not exhaust non-lethal methods, including failing to move the sheep to another land, not having human presence by the herd and not removing sheep carcasses. The pack also has pups, Weiss’ group said, adding that if adults are killed, the young wolves may die from lack of food.

The events are reminiscent of the 2012 wolf attacks on cattle in northern Stevens County that didn’t end until the state was forced to use helicopter gunners to kill all seven members of the Wedge Pack.