Timeline: Missing Iranian nuclear scientist surfaces

A missing Iranian nuclear scientist, who Tehran says was kidnapped by the CIA, has turned up at the Iranian interests section of Pakistan's embassy in Washington DC and wants to return home immediately.

Here is a timeline of events involving Amiri:

June 2009 - Shahram Amiri, a university researcher working for Iran's Atomic Energy Organisation, goes missing during a pilgrimage to Saudi Arabia. Iran's Press TV said Amiri was a researcher at Tehran''s Malek Ashtar University.

Sept. 2009 - The IAEA says Iran, three months after Amiri's disappearance, disclosed the existence of its second uranium enrichment site, near the central holy Shi'ite city of Qom, further heightening tension over the Islamic state's atomic activities. Construction of the plant began in 2006.

Oct. 2009 - Foreign minister Manouchehr Mottaki says Iran has found documents that prove US involvement in the disappearance.

Dec. 2009 - Iran accuses Saudi Arabia of handing over the scientist to the United States.

March 2010 - Media reports that Amiri defected as part of a long-planned operation to get him to leave Iran and resettle in the United States.

-- An ABC report says Amiri has been extensively debriefed since his defection and says he helped to confirm US intelligence assessments about the Iranian nuclear programme.

June 2010 - Iran's state television shows a video of what it says is the missing nuclear scientist declaring he was kidnapped and taken to the United States where he was "tortured".

-- "I was kidnapped from Medina in a joint operation by the American intelligence service ... and Saudi Arabia," Amiri says, speaking in Farsi, in footage which showed him sitting behind a computer wearing headphones. Amiri says in the video he is in Arizona and that the footage was taken on April 5.

-- Shortly after that footage, a second video appears on the Internet, also purporting to be Amiri, in which he says he is actually studying in the United States.

-- Iran summons the Swiss ambassador in Tehran and hands over documents which it says shows the missing scientist has been kidnapped by the United States.

-- On June 29, in a third video, a man describing himself as Amiri said he had fled from US "agents" and was in hiding, urging human rights groups to help him to return to Iran.

July 2010 - Iran has sent to US authorities more documents about the disappearance of the scientist, demanding his release, the foreign ministry says on July 3.

-- "The documents about Shahram Amiri's abduction by the CIA have been delivered to the Swiss embassy as the preservers of America's interests," according to Iran's IRNA.

-- The scientist has taken refuge in the Iranian interests section of Pakistan's embassy in Washington, a Pakistan foreign ministry official says.