FILE -  In this April 8, 2008 file photo provided by the Iranian President's Office, Iranian President Mahmoud Ahmadinejad, center, visits the Natanz Uranium Enrichment Facility some 200 miles (322 kilometers) south of the capital Tehran. Iran is on threshold of boosting output of material that can be turned quickly into weapons-grade uranium at an underground plant that is heavily fortified against attack, diplomats told The Associated Press on Thursday, Nov. 15, 2012. (AP Photo/Iranian President's Office, File) NO SALES