Iranian nuclear scientist Shahram Amiri, who Tehran claimed was kidnapped by the United States intelligence agents last year, has left U.S. for the Iranian capital city of Tehran, local satellite channel Press TV reported Wednesday.

Amiri, who disappeared one year ago, emerged on Tuesday in the Pakistani Embassy in Washington where he was taking refuge, and demanded to immediately return to Iran, Press TV reported.

The Pakistani embassy represents the Iranian interest section, as Iran and the United States currently have no diplomatic relations.

According to Iranian media reports, Amiri went missing during pilgrimage to Mecca in Saudi Arabia in June 2009.

According to two videos and one audio message featuring the nuclear scientist obtained by Iran's intelligence sources, Iran believed that Amiri was abducted by the U.S. intelligence service Central Intelligence Agency (CIA).

Although the two videos contradicted with each other regarding the reason of his missing, Amiri's latest audio message revealed that he was offered 10 million U.S. dollars to appear on CNN and announce that he had willingly defected to the U.S..

Iran had urged the swift and unconditional release of the scientist.

Analysts say U.S. intelligence officials decided to release Amiri after they failed to advance their propaganda campaign against Iran's nuclear program via fabricating interviews with the Iranian national, said Press TV.