The American Museum of Natural History, one of the country’s largest museums whose prestige was built in part on excavating Native American gravesites, is shuttering some of its longtime exhibits that display cultural materials that could be subject to return to tribal nations.

The move comes as the New York City museum and many others, including the Field Museum of Natural History in Chicago, consult with tribes and evaluate their compliance with new federal regulations intended to speed up the process of returning ancestral remains and sacred items under the Native American Graves Protection and Repatriation Act. ProPublica published a series of articles last year, called “The Repatriation Project,” about the failures of museums to comply with the law in the past three decades.

Sean Decatur, president of the American Museum of Natural History, told staff in a letter on Friday that the “Eastern Woodlands and Great Plains Halls” will be closed to the public starting Saturday. The letter, provided to ProPublica, was first reported by The New York Times. Both exhibit halls, which contain numerous items from tribes in Montana, the Dakotas, Wisconsin and other states, are “severely outdated,” Decatur said.

“While the actions we are taking this week may seem sudden, they reflect a growing urgency among all museums to change their relationships to, and representation of, Indigenous cultures,” Decatur wrote to staff. “The Halls we are closing are vestiges of an era when museums such as ours did not respect the values, perspectives, and indeed shared humanity of Indigenous peoples.”