ISNA news agency referred to "some rumors" that Shahram Amiri, who went missing during a pilgrimage to Saudi Arabia in June, was an employee of Iran's Atomic Energy Organization who wanted to seek asylum abroad.
But Foreign Minister Manouchehr Mottaki did not confirm this when he made the allegation against the United States, which suspects the Islamic Republic is seeking to develop nuclear bombs. Iran denies the charge.
"We have found documents that prove U.S. interference in the disappearance of the Iranian pilgrim Shahram Amiri in Saudi Arabia," he told reporters, according to the website of state Press TV, without giving details.
Press TV said Amiri was a researcher at Tehran's Malek Ashtar University, but did not give details. It quoted his wife as saying he had not contacted his family except for a few phone calls he made at the beginning of his trip.
Malek Ashtar is involved in the implementation of "special national research projects" and has faculties in aerospace, electrical engineering and other topics, according to the university website .
His disappearance came months before the disclosure of a second uranium enrichment facility that Iran has been building near the city of Qom.
(Reporting by Parisa Hafezi and Reza Derakhshi; writing by Fredrik Dahl)
