Conservationists sued the federal government Friday over changes to a reintroduction program for the endangered Mexican gray wolf.

The U.S. Fish and Wildlife Service announced the first major changes to the program since 1998 earlier this week. Under them, wolves can roam a greater expanse of Arizona and New Mexico and will be released from captivity at more sites.

The Center for Biological Diversity and Defenders of Wildlife say limiting wolves that are reintroduced into the wild to 325 doesn't allow for recovery of the species. They also say wolves would be deprived of prime habitat north of Interstate 40 and would be at a greater risk of being killed.

Interior Secretary Sally Jewell and Fish and Wildlife are named as defendants. Neither responded Friday to requests for comment.