If Yale doesn’t return the artifacts that explorer Hiram Bingham brought to New Haven from Machu Picchu in the early 1900s, Peru’s president, Alan Garcia, said he will consider the University no better than a common thief.

“Either we come to an understanding regarding Machu Picchu, or we’ll simply have to describe them as looters of our treasuries,” Garcia said of Yale on Monday, according to Reuters. If the University doesn’t respond, he said, “silence would indicate that they are guilty of robbery.”

Yale and Peru have been locked in a legal battle over the artifacts since April 2009. Peru’s newly-appointed minister of culture has sworn to make the retrieval of the artifacts his top priority.