Amiri, a researcher at Tehran's Malek Ashtar University, mysteriously disappeared in June 2009 while on a religious pilgrimage to Saudi Arabia, according to Iranian media reports.
Iran has accused the United States of involvement in Amiri's disappearance, saying the researcher was taken to force him to give up data about Tehran's nuclear program. The U.S. State Department has denied that charge, but has been tight-lipped on whether Amiri defected.
"Iranian scientist Shahram Amiri, who was kidnapped by the Americans, had gone to the Pakistani Embassy in Washington, D.C. and taken refuge at Iran's Interest Section. He has requested to be sent back to Iran quickly," Iran's semiofficial news agency Mehr said Tuesday.