In this April 8, 2008 file photo released by the Iranian President's Office, Iranian President Mahmoud Ahmadinejad, front center, visits the Natanz Uranium Enrichment Facility some 200 miles (322 kilometers) south of the capital Tehran, Iran. Technicians upgrading Iran's main uranium enrichment facility have tripled partial or full installations of high-tech machines that could be used in a nuclear weapons program to more than 600 since starting their work three months ago, according to diplomats who demanded anonymity because they said they are not authorized to disclose the information, Wednesday April 17, 2013. (AP Photo/Iranian President's Office, file)