The US asked Iran to release its citizens Robert Levinson, Amir Hekmati and Saeed Abedini, ITAR-TASS cites Secretary of State John Kerry.
Robert Levinson, 60, from Coral Springs (Florida) disappeared in Iran in March 2007. He was last seen in Kish. Levinson had worked at the FBI and quit the job about 15 years ago.
Iranian special services told the US that they did not know his location. Washington believes that the man may be detained by extremists in Iran, Afghanistan and Pakistan.
Hekmati is in prison for espionage and Abedini was jailed for religious views.
