An American fugitive living in Iran since he murdered an Iranian opposition activist in the US in 1980 has revealed that he met a former Federal Bureau of Investigation agent shortly before the latter disappeared on the Iranian island of Kish a month ago.

US authorities have been anxiously seeking information about the former agent, Robert Levinson, for several weeks. The Iranian foreign ministry says it is trying to clarify his whereabouts. US officials suspect he is in Iranian detention.