Two conservation groups have filed a lawsuit that seeks to stop the state from killing any more wolves.

The Center for Biological Diversity and Cascadia Wildlands said in a news release that the lawsuit was filed Monday in Thurston County Superior Court.

The lawsuit asserts that the Washington Department of Fish and Wildlife's killing of wolves in two packs in the northeastern part of the state relied on a faulty protocol and failed to undergo required environmental analysis.

Agency spokesman Bruce Botka told The Associated Press Monday that officials haven't had time to review the documents and don't have an immediate response to the suit.

The agency has approved killing wolves in an effort to stop attacks on cattle. Officials have said they authorize incremental lethal control of wolves in accordance with established protocols after nonlethal prevention techniques fail.