Foreign Minister Manouchehr Mottaki said on Sunday that Iranian nuclear scientist Shahram Amiri, who Tehran says has been kidnapped by US agents, is currently in the United States.
"Based on latest comments, at least the Americans are aware of the whereabouts of Shahrim Amiri, although existing evidence indicates he is in America," Iran's ISNA news agency quoted Mottaki as telling a group of students in Tehran.
ABC news in the United States reported last month that Amiri, an Iranian nuclear physicist in his early 30s who disappeared in June 2009 after arriving in Saudi Arabia on a pilgrimage, had defected and was working with the CIA.
Iranian officials maintain that Amiri was abducted from Saudi Arabia by US agents while on pilgrimage to the Muslim holy places.
The ABC report said that US agents described the defection as "an intelligence coup" in efforts to undermine Iran's controversial nuclear programme.
Amiri's disappearance "was part of a long-planned CIA operation to get him to defect," ABC reported.
The United States has pressed hard for tougher international efforts to rein in Iran's nuclear programme, amid Western suspicions it is cover for a weapons drive.
Tehran insists its nuclear programme is entirely peaceful and designed to meet medical research and domestic energy needs.
Mottaki also told students that, under guidelines issued by supreme leader Ayatollah Ali Khamenei, resuming ties with the United States broken off in the aftermath of the 1979 Islamic revolution was "not on the agenda."
Earlier on Sunday, Khamenei slammed US President Barack Obama for issuing what he said was a threat of "nuclear attack" against Iran.
Washington on Tuesday unveiled a new nuclear policy which limits the use of the US nuclear arsenal but makes exceptions for "outliers" Iran and North Korea.