BOISE –(AP) Idaho wildlife officials have killed 23 wolves in northern Idaho in an effort to boost the number of elk in the region.

The Idaho Fish and Game announced Friday afternoon that the animals were killed by USDA Wildlife Service agents using a helicopter in the Lolo elk zone near the Montana border. It's the sixth time the agency has taken action to kill wolves in the Lolo zone in the past four years, bringing the total number of wolves killed there to 48.

Suzanne Stone, an Idaho spokeswoman for the wildlife advocacy group Defenders of Wildlife, said she was disappointed by the news. Stone said the state agency didn't reveal their plans when her organization asked earlier this year about possible predation efforts in northern Idaho.