Vanished Iranian scientist turns up in Washington

Iran, which is locked in a standoff with the West over its suspected pursuit of nuclear weapons, has repeatedly accused the CIA of abducting Shahram Amiri, who worked for Iran's Atomic Energy Organisation.

Amiri, who went missing during a pilgrimage to Saudi Arabia more than a year ago, appeared at the Iranian interests section of the Pakistani embassy, which represents Iran in the United States because Tehran and Washington have no diplomatic relations.

A man identifying himself as Amiri has variously said in recent videos that he was kidnapped and tortured; that he was studying in the United States; and that he had fled U.S. agents and wanted human rights groups to help him return to Iran.

Amiri was quoted by Iranian state TV on Tuesday as saying "my kidnapping was a disgraceful act for America."

The mystery surrounding Amiri fueled speculation that he may have information about Iran's nuclear program sought by U.S. intelligence. In March, ABC News reported that Amiri had defected and was helping the CIA.

U.S. officials on Tuesday gave no explanation of why he had come to the United States and said he decided to return to Iran of his own volition.