Wolf supporters on Wednesday made good on a September pledge and filed suit to force the federal government to develop a broader recovery plan for gray wolves across more of the U.S.

The Center for Biological Diversity filed suit in federal district court in Washington against the U.S. Fish and Wildlife Service for violating the Endangered Species Act by never developing a comprehensive recovery plan for gray wolves nationwide.

According to 2014 federal court rulings, under the Endangered Species Act, wolves must remain protected until the Fish and Wildlife Service implements a national plan.

But the federal agency in June went the opposite direction, saying it would yet again file a formal plan later this year to remove wolves from federal protections entirely because they have recovered in enough places to ensure their survival as a species - including Minnesota, Wisconsin and Michigan.

Wolf supporters say there's not enough wolves in enough places.

"We won't let the Trump administration bring wolf recovery to a screeching halt to benefit the blood sport of trophy hunting," said Collette Adkins, a Minnesota-based biologist and attorney for the Center for Biological Diversity. Adkins said that, if successful, the lawsuit would require the feds to recover wolves nationwide and would also block efforts to "prematurely" remove protections for wolves

The Fish and Wildlife Service has tried multiple times - through the Clinton, Bush and Obama administrations - to delist wolves in Minnesota, Wisconsin and Michigan, saying the big predators have fully recovered here after brushing with extinction in the 1960s and '70s.

The most recent of those delisting efforts, in 2012, allowed state agencies to hold wolf trapping and hunting seasons for three years, until late 2014 when a federal judge ruled that the agency had erred in taking wolves off the endangered list too soon.

That December 2014 ruling was upheld in 2017 by a federal appeals court decision that continues to protect wolves across the region today.

Several bills have been introduced in Congress, including this year, to end federal protections for wolves and override the court action. So far, none of those has passed both the House and Senate. Livestock and some hunting groups say wolf numbers are already too high - especially in Minnesota, Wisconsin and parts of the Rockies - and that wolf numbers need to be culled through hunting and trapping seasons.

Wolf supporters say they want a federal plan to allow wolves to roam beyond where they are now into more areas they occupied before European settlement and before widespread wolf killing nearly forced the animal's extinction. They say a new recovery plan also would enable wolves to establish viable populations in areas where small populations are still recovering, such as California, Oregon and Washington.

The Minnesota Department of Natural Resources estimated last year that the state has about 2,856 wolves. The Wisconsin DNR earlier this year said there are as many as 944 wolves in the state, down about 2 percent from the estimated 956 last year, the state's modern-day record. Michigan's Upper Peninsula has more than 500 wolves.