That split listing is rare, and in its proposal, the wildlife service admits that it is not allowed under the 1973 Endangered Species Act.
Animal welfare groups cheered the proposal.
“I thank the U.S. Fish and Wildlife Service for its thorough scientific review of the chimpanzee’s status and for the intention to protect chimpanzees from harm and exploitation regardless of whether they are in the wild or in captivity," said Jane Goodall, the founder of the Jane Goodall Institute, in a statement.
Wayne Pacelle, president and chief executive of the Humane Society of the United States, added, "It’s critical that the United States take forceful action to protect chimps in the wild and in captivity, in order to assure the survival of future generations of chimpanzees in their native habitats.”
Research organizations have warned that the endangered listing could harm research on Hepatitis C and other diseases.
"Human and chimpanzee lives will be lost as a result of the reclassification," said the Texas Biomedical Research Institute, which houses a primate research center that studies chimps, in a statement. "It is as simple and tragic as that."
Conservation groups, meanwhile, point to a study from the Institute of Medicine that found that "most current use of chimpanzees for biomedical research is unnecessary," though it noted a possibility that chimps have a role in some research, including developing a vaccine for Hepatitis C.
In 2010, a group of organizations, including the Humane Society and the Jane Goodall Institute, petitioned the wildlife agency to change its rules and call all chimpanzees endangered. That petition led to Tuesday's announcement.
The change in designation is one area that advocates had been hoping the federal government would address. They also expect the National Institutes of Health to announce that it will retire most of the chimps it owns for research, a decision recommended by an advisory panel in January.
In the wild, chimpanzees live across 22 countries in Africa, though they have been threatened by deforestation, poaching and outbreaks of disease. Animal groups claim some of that poaching has been spurred by the demand for chimps for personal and research purposes.
In the last 30 years, wild populations have fallen by more than 65 percent.
The proposal will be published in the Federal Register on Wednesday, and the wildlife service is accepting comments through Aug. 12.
-- This story was updated at 4:08 p.m.