FLAGSTAFF, Ariz. (AP) – Archaeologists curious about American Indian cultures dug up human remains and associated funerary objects at Canyon de Chelly decades ago, while some remains were taken for protection from erosion in the canyon with towering red, sandstone walls.

Whatever the reason, the Navajo Nation wants hundreds of sets of human remains exhumed from the national monument on their reservation to be returned for proper burial, contending the tribe is the rightful owner of them. The Navajo Nation, whose members live on the country’s largest American Indian reservation, contend in a lawsuit filed last week that despite their demands for the remains, the National Park Service has unrightfully held them in a collection in Tucson.

Since 1931, the federal agency has been charged with preserving the thousands of artifacts and ruins within the national monument near Chinle. But the land revered by Navajos as sacred remains tribally owned.

Canyon de Chelly Superintendent Tom Clark said the Park Service’s goal is to repatriate the items, but it first must determine whether any other tribes have cultural affiliation to them under a 1990 federal law known as the Native American Graves Protection and Repatriation Act. Clark said that law appears to conflict with the property rights of the Navajo Nation.

“Until we see how this plays out, we would not proceed to aggravate the situation,” he said Tuesday. “But we’ll see how it actually plays out and determine from there. Obviously other tribes are interested in it, too.”

Canyon de Chelly has been inhabited for thousands of years, with artifacts and cliff dwellings lining the canyon walls dating from the 4th to 14th centuries. Clark said Zuni Pueblo, the Hopi Tribe, Apaches, Utes or other tribes could have rightful claims to the remains.

The Navajo Nation – which calls the canyon “tsegi” or “within the rock” – believe that digging up human remains causes illness to the living, including arthritis and depression, and damages the environment. The tribe said it never agreed to let the Park Service or any other entity carry off remains or cultural objects located on the monument because that would have contradicted traditional Navajo laws and violated the rights of tribal members.

“Since at least 1868, this has been the heart of Navajo country, and nothing in the act that created the national monument changed that,” said Alan Downer, director of the tribe’s Historic Preservation Department. “So for the Park Service to say, `we dug it up, put it in our collection and, therefore, it’s ours’ is wrong.”

The tribe further argues that the remains were taken before Congress outlined a process for museums and federal agencies to inventory their collections, consult with tribes regarding cultural affiliation and return remains to the appropriate tribe. Congress has allowed the Park Service to hold the objects and remains only temporarily to preserve and protect them at most, the tribe said.

The most recent excavation in Canyon de Chelly took place in 1988 when the tribe agreed to let the Park Service remove remains from an eroding arroyo under the condition that they be reburied soon after, Downer said. Instead, they ended up in the Park Service’s collection, he said. Other excavation work was done as early as the 1890s.

The Park Service met with tribes in June and showed them its collection. Downer said some of the pottery clearly is Navajo as are remains recovered from Massacre Cave, where 115 Navajos were killed in a bloody encounter with the Spanish in 1805.

“When you get to pre-contact times, it’s very difficult to say `this is unquestionably ancestral to this contemporary tribe,”’ Downer said.

Clark said the Park Service doesn’t claim ultimate ownership of the remains or objects but must follow the mandate of Congress.

“We all want to have the remains repatriated, that’s what all the tribes and the Park Service have all stated,” he said. “That is our goal. I guess the disagreement is in the process to get there.”

The Navajo Nation is asking a judge to declare that the remains are the property of the tribe and order the Park Service to immediately return them. Should the court determine that federal laws transferred the title of human remains and cultural objects from the tribe to the Park Service, the Navajo Nation wants those laws declared void.