His lawyer, Paul O'Dwyer, told CNN on Monday that Hassan Golkanbhan feared persecution over his opposition to the Iranian government and that his wife and two children had fled Iran for an undisclosed safe haven.
"He's afraid to return to Iran … He's perceived as not being a supporter, or being an opponent of the Iranian regime," O'Dwyer said. "Somebody who has betrayed the regime and who can no longer be trusted by them."
The lawyer said suspicions about Golkanbhan's political views had arisen during the trip, on which Ahmadinejad addressed the world body for the last time as president amid mounting pressure over Iran's nuclear programme.
"There were things that he was expected to do that he was uncomfortable with doing," O'Dwyer said, without providing further details. "While he was here … his position on certain things became known to the Iranian government."
O'Dwyer declined to comment on Golkanbhan's whereabouts, but said he was awaiting an asylum interview with US authorities that could take months.
The US and its allies have ramped up sanctions in recent years to try to halt Iran's nuclear program, which Western nations and Israel view as part of a secret effort to develop a nuclear weapon.
Israel – the sole if undeclared nuclear-armed state in the Middle East – has hinted it may take military action if Iran crosses a "red line" in its uranium enrichment.
Iran insists its program is entirely peaceful and has vowed massive retaliation for any attack on its territory.
The US has had no diplomatic relations with Iran since the 1979 revolution brought a hardline anti-American regime to power, but Iranian leaders have been allowed to visit and address the annual UN assembly. – Sapa-AFP