BILLINGS, Mont. - Federal wildlife officials have drafted plans to lift protections for gray wolves across the Lower 48 states, a move that could end a decades-long recovery effort that has restored the animals but only in parts of their historic range.

The draft U.S. Department of Interior rule obtained by The Associated Press contends the roughly 6,000 wolves now living in the Northern Rockies and Great Lakes are enough to prevent the species' extinction. The agency says having gray wolves elsewhere - such as the West Coast, parts of New England and elsewhere in the Rockies - is unnecessary for their long-term survival.

A small population of Mexican wolves in the Southwest would continue to receive federal protections, as a distinct subspecies of the gray wolf.

The loss of federal protections would be welcomed by ranchers and others in the agriculture industry, whose stock at times become prey for hungry wolf packs. Yet wildlife advocates say the proposal threatens to cut short the gray wolf's dramatic recovery from widespread extermination.

The proposal was first reported by the Los Angeles Times.

The U.S. Fish and Wildlife Service said Friday the rule was under review and would be published in the Federal Register and opened to public comment before a final decision is made.

If the rule is enacted, it would transfer control of wolves to state wildlife agencies by removing them from the federal list of endangered species. The government has been considering such a move since at least 2011, but previously held off given concerns among scientists and wildlife advocates who warn it could effectively halt the species' expansion.

John Vucetich, a wolf specialist and biologist at Michigan Tech University, said suitable habitat remains in large sections of the Rockies, the nation's midsection and the Northeast. Wolves presently occupy only about 15 percent of their historical range, but that could be greatly expanded if humans allow it, he said.

"It ends up being a political question more than a biological one," Vucetich said. "It's very unlikely the wolves will make it to places like the Dakotas and the Northeast unless the federal government provides some kind of leadership."

Meanwhile, increasing wolf numbers in parts of the country have stirred a backlash from agricultural and hunting groups upset by the predator's attacks on livestock and big game herds such as elk. Their complaints spurred Western lawmakers two years ago to remove wolves from the endangered list in five states by force, after the issue got bogged down by environmentalists' lawsuits.

Paul Schlegel with the American Farm Bureau Federation said any step toward dropping wolves from the endangered list would be welcome to ranchers who have lost cattle, sheep and other animals to wolves or fear they might if the predators enlarge their territory.

"There's a lot of anxiety when a listed species attacks your livestock and you have no way of protecting them," he said.

The National Cattlemen's Beef Association said the government also should remove protections for wolves in the Southwest, where agencies have struggled to re-establish wolves in parts of New Mexico and Arizona. That population is believed to number only about 75 animals.

"Repeated failed attempts to achieve unnaturally high population levels in that region have put undue strain on livestock producers" and government resources, spokesman Chase Adams said.

Some biologists have argued wolves will continue spreading regardless of their legal status. The animals are prolific breeders, known to journey hundreds of miles in search of new territory. They were wiped out across most of the U.S. early last century following a government sponsored poisoning and trapping campaign.

In an emailed statement, the Fish and Wildlife Service pointed to "robust" populations of the animals in the Northern Rockies and Great Lakes as evidence that gray wolf recovery "is one of the world's great conservation successes."

Wolves in those two areas lost protections under the Endangered Species Act over the last two years. Advocacy groups have filed federal suits challenging decisions to lift protected status from wolves in Wyoming, Michigan, Minnesota and Wisconsin.

"The U.S. Fish and Wildlife Service is evaluating the appropriate management status of the gray wolf under the Endangered Species Act outside of these recovered population areas," the agency said in its Friday statement. "This is a matter still under internal review and discussion."

In some states where wolves have recovered, regulated hunting and trapping already has been used to drive down their populations, largely in response to wolf attacks on livestock and big game herds. The U.S. Fish and Wildlife Service recently released data showing wolf numbers dropped 7 percent last year in the face of newly-expanded hunting and trapping seasons in Idaho, Montana and Wyoming. That's the most significant decrease since they were reintroduced in the mid-1990s.

"There's a race to the bottom to see who can be more anti-wolf," said Don Barry, a former Interior Department assistant secretary under President Bill Clinton and now a vice president at Defenders of Wildlife. "They're basically giving up on wolf recovery before the job is done."

Federal officials have said they are monitoring the states' actions, but see no immediate threat to the gray wolf's survival.

In Oregon and Washington, which have small but rapidly growing wolf populations, the animals remained protected under state laws even after federal protections were lifted in portions of the two states.

Between 1991 and 2011, the federal government spent $102 million on gray wolf recovery programs and state agencies chipped in $15.6 million. Federal spending likely would drop if the proposal to lift protections goes through, while state spending would increase.