The comments by Deputy Foreign Minister Abbas Araghchi appear aimed at calming Iranian hard-liners who oppose rapidly easing the 34-year diplomatic freeze with the United States.
Some critics of Iranian President Hassan Rohani shouted insults after his return from an annual United Nations gathering in New York, which included a groundbreaking 15-minute call with U.S. President Barack Obama.
Araghchi was quoted by the Fars news agency Sunday as saying "normal relations" with Washington will need more than "a phone call, meeting or negotiations" - a reference to Iran's efforts to restart stalled talks over its nuclear program.
The United States and Iran broke ties after the 1979 Islamic Revolution.
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