Environmental and animal rights groups are suing the federal government in hopes of restoring endangered species protections for gray wolves in the Northern Rockies.

The U.S. Fish and Wildlife Service had removed the region’s 1,500 wolves from the endangered list in March, turning over management responsibilities to state officials in Idaho, Wyoming and Montana.

The lawsuit alleges those states lack adequate laws to ensure wolves are not again eradicated from the region.

An attorney for Defenders of Wildlife says the groups will seek an immediate injunction to suspend state management until the case is resolved. Defenders of Wildlife is one of twelve groups that filed the suit Monday in U.S. District Court in Missoula.