NEW YORK — A U.S. animal rights group has filed what it said is the first lawsuit seeking to establish the "legal personhood" of chimpanzees.

The non-profit Nonhuman Rights Project asked a New York state court to declare a 26-year-old chimp named Tommy "a cognitively complex autonomous legal person with the fundamental legal right not to be imprisoned."

The lawsuit filed Monday seeks a declaration that Tommy's "detention" in a "small, dank, cement cage in a cavernous dark shed" in central New York is unlawful and demands his immediate release to a primate sanctuary.

Chimpanzees "possess complex cognitive abilities that are so strictly protected when they're found in human beings," Steven Wise, the president of Nonhuman Rights Project, told Reuters.

"There's no reason why they should not be protected when they're found in chimpanzees," he added.

The lawsuit on Tommy's behalf is among three the group is filing this week on behalf of four chimps across New York. The other chimps are Kiko, a 26-year-old chimp living on a private property in Niagara Falls, and Hercules and Leo, two young male chimps used in research at Stony Brook University on Long Island, the group said.

Tommy's owners, Patrick and Diane Lavery, and Stony university did not immediately return requests for comment. Kiko's owners could not be reached for comment..

The Nonhuman Rights Project used its own research to find the chimps, and Wise first visited Tommy in October after reading a local newspaper article about exotic animals kept at the Laverys' used trailer lot in Gloversville, New York, about 50 miles northwest of Albany.

"He looked terrible," said Wise, who previously observed healthy, wild chimps in Uganda. "Hey looked like a caged chimpanzee - they don't move, they don't look at you. They look depressed."

The lawsuit states that chimps are entitled to a "fundamental right to bodily liberty," which Wise told Reuters is the basic right to be left alone and not held for entertainment or research.

The lawsuit was filed at "the earliest point at which we have some reasonable chance at winning," said Wise, a well-known animal rights activist and author of books including the 2000 title "Rattling the Cage: Toward Legal Rights for Animals."

"These are the first cases in an open-ended, strategic litigation campaign," he said. "We're just going to keep filing suits."

Nonhuman Rights Project in 2007 began a nationwide search for an optimal venue to file the lawsuits, Wise said. New York was ultimately chosen because of its generally flexible view of requests for a writ of habeas corpus, the centuries-old right in English law to challenge unlawful detention, he said.

David Favre, a professor at Michigan State University College of Law and an expert on animal law, said it is the first habeas petition filed on behalf of an animal.

"The focus here is whether a chimpanzee is a 'person' that has access to these laws," said Favre.

The lawsuits come as medical authorities re-examine the employment of chimpanzees in research in light of new technology that renders the use of chimpanzees less necessary.

In a decision applauded by animal rights groups, the U.S. National Institutes of Health in January said it was reducing its use of chimps in biomedical research, retiring most to sanctuaries. At the time, NIH Director Dr. Francis Collins called chimps "very special animals" that deserve "special consideration."