This story has been updated.
Shahram Amiri, the Iranian nuclear scientist in the middle of a high-stakes battle between Washington and Tehran, has taken refuge in a Pakistani embassy building in Washington, D.C. and will leave for Iran within the next 48 hours.
Iranian official Ali Shirazi confirmed to ABC News that Amiri is now in the Iranian interests section building, which is under the auspices of the Pakistani diplomatic mission to the U.S. A senior Pakistani official told ABC News that Amiri arrived at the Iranian building at 6:30 p.m. Monday and asked to go home. Both Iranian and Pakistani officials told ABC News that Amiri will leave the U.S. within the next 24 to 48 hours.
Secretary of State Hillary Clinton said Amiri has been in the United States "of his own free will."
"His is free to go," said Clinton. "He was free to come. These decisions are his alone to make."
Clinton said that Amiri was actually scheduled to travel to Iran on Monday "but was unable to make all the of the necessary arrangements to reach Iran through transit countries."
Another U.S. official said Amiri's decision to return home "gives the lie to the idea he was tortured or imprisoned. He can tell any story he wants -- but that won't make it true." The official said Amiri "came to this country freely, he live there freely, and he has chosen freely to return to Iran."
While Iranian authorities claim Amiri was abducted in Saudi Arabia in 2009 and brought to the U.S. against his will, U.S. intelligence officials say Amiri defected to the U.S. voluntarily after working for several years as a CIA spy and providing crucial details about Iran's burgeoning nuclear weapons program.
According to people in the U.S. intelligence community briefed by the CIA, the Iranian government threatened to harm Amiri's family unless he returned home. He left a wife and son behind.
In two videos released at the end of June, Amiri claimed to have "escaped" U.S. intelligence and said he was on his way back to Iran.
On the videos, Amiri claimed that he escaped "U.S. intelligence officers in Virginia." He said he was now in a "safe place" but that he was in "danger and could possibly be arrested again by U.S. intelligence officers at any moment." He has also claimed that he was tortured by U.S. officials.
"In case anything happens to me or if I do not make it back home safely, the responsibility will solely rest on the officials of the United States," Amiri said in a video posted to YouTube, which was apparently recorded June 14.
After the release of the videos, a U.S. official disputed Amiri's claims.
"The guy's ability to make and release messages is clear proof that he hasn't been held in the United States against his will," said the official. "That's not the way it works -- we don't have to compel people to defect. Maybe he's just trying to build a story for the folks back home. The fact that he can say what he wants doesn't make his statements true. He's shown to the world that he has the power to make choices -- even bad ones."
The second of the two videos aired on Iranian state television, continuing the effort of Tehran to show Amiri was kidnapped and brought to the U.S. against his will.
In fact, U.S. officials say, Amiri was a key spy inside the Iranian nuclear program for several years before his defection.
Amiri's precise role in U.S. intelligence gathering remains unclear. Former and current intelligence officials told ABC News that Amiri confirmed the existence of a secret underground enrichment facility near Qom and also described him as a key source in the conclusions of the 2007 National Intelligence Estimate, which found that Iran had suspended its nuclear weaponization program. Initially, before Amiri defected back to Iran, the same officials told ABC News that Amiri's information had contradicted the 2007 NIE finding, but further reporting indicates that was an incorrect interpretation.
CIA director Leon Panetta acknowledged in June to ABC News that the CIA no longer believed the conclusions of the 2007 NIE, saying that Tehran continues "to work on designs" for a nuclear weapon.
"I think they continue to develop their know-how," Panetta said. "They continue to develop their nuclear capability."
Iran and Nuclear Weapons
Iran's nuclear ambitions have been the subject of international debate. The Obama administration recently called for increased U.N. sanctions. Amiri, once a star scientist for the Iranian nuclear program,according to U.S. officials, has become the center of efforts of both countries to characterize Iran's nuclear ambitions.
Tehran has said that its nuclear program is for energy purposes only and denies ambitions for a nuclear weapon.
Iranian intelligence and the CIA posted dueling videos of the scientist earlier this year. In one video, Amiri claimed the U.S. kidnapped, drugged and tortured him, in the other he said he was happy to be in the U.S. CLICK HERE TO SEE THE DUELING VIDEOS
CIA officials pushed for Amiri to flee the country out of fear that his disclosures might have exposed him to Tehran as a spy.
Amiri vanished last June during a pilgrimage to Saudi Arabia. The Iranian government claimed then that their scientist, a professor at Tehran's Malek Ashtar University, had been kidnapped by the CIA. In fact, say U.S. officials, the CIA, with the help of the Saudi government, whisked Amiri to the U.S., where he was to permanently resettle.
U.S. Discovered Hidden Enrichment Facilities, Video Dueling Began
A few months after Amiri arrived, the Obama Administration announced that U.S. intelligence had discovered a second, hidden nuclear enrichment facility in the Iranian city of Qom.
Then came the alleged threats by Iranian intelligence, which set off the bizarre battle of dueling videos that were released earlier this month. The first, which was broadcast on Iranian state television, shows Amiri speaking to a computer camera and announcing that the U.S. had drugged and kidnapped him and forced him to Tucson, Arizona.
He appeared to be looking down at a script as he spoke.
According to the two current U.S. officials, Amiri called home earlier this year because he missed his family. On a second call, Iranian intelligence answered and threatened to harm his son, unless he taped an internet video saying he'd been kidnapped. Amiri, fearing for his family, agreed, according to a person briefed on the case.
"He missed his son," said the person. "And he couldn't help calling home to speak to him." Within days, the CIA learned that Amiri had given the Iranians a video and moved quickly to produce a version of its own. The second video shows Amiri well-dressed and manicured with a globe - turned to North America -- and chess set behind him as he appears to read from a teleprompter. He says, in Farsi, that he is happily living in the U.S. and going to school. He also denied having worked in the Iranian nuclear program and made a plea to his wife and son. "I want them to know that I never abandoned then, and that I will always love them."
According to one U.S. official, the CIA intended to produce the video and launch it on the internet before the Iranians had a chance to air their version.
Instead, the video languished at CIA headquarters for weeks, according to a senior intelligence official. Then, in early June, Iranian state television aired the Amiri video. Within a day, the CIA posted their Amiri video on YouTube, with a user identification of "shahramamiri2010."
The Iranian government then formally requested that the U.S. government return Amiri, accusing the Americans of holding him against his will. A spokesperson for the State department acknowledged that the U.S. government received the request, but had no further comment.