NEW YORK (AP) — U.S. officials say they have returned enough dinosaur skeletons to the government of Mongolia to stock a museum.

James T. Hayes leads the New York office of Homeland Security Investigations. He says a sizeable portion of at least 31 fossilized dinosaur remains was returned to Mongolian authorities on Thursday. The announcement was made at a Manhattan ceremony.

Hayes says the effort to intercept illegal shipments of dinosaur bones shows the U.S. “will not allow the illicit greed of some to trump the cultural history of an entire nation.”

Hayes says the bones will be displayed at a national museum in Mongolia because they don’t belong in the hands of any private collection or one owner.

The bones were recovered after U.S. Immigration and Customs Enforcement agents discovered illegal shipments.