The U.S. Fish and Wildlife Services (FWS) published a final rule in the Federal Register on Wednesday that formally returns about 4,000 gray wolves in the Upper Midwest to the federal endangered species list.
The rule fulfils a deal made with environmental groups in July when the agency promised to reinstate the wolves' protected status while considering its next move.
The new designation makes it illegal for landowners to kill wolves they catch in the act of preying upon livestock, pets or guard animals.
Earlier this year, the government dropped the wolves in Michigan, Minnesota and Wisconsin from the endangered list, turning the management of the predators over to state wildlife regulators.
Activists groups filed a lawsuit challenging the decision, arguing that the government broke the law when it issued its ruling because it did not provide public notice or invite public comments.
In the settlement, FWS officials agreed that they erred in not offering a public comment period, as required by law. But officials said they fully expect the animals will eventually be removed from the protected list.