Ayatollah Ali Khamenei told military commanders today that Iran will resist "coercion and excessive demands."
Khamenei made the remarks as negotiators from Iran and six world powers launched a new round of talks focused on reaching a final deal that curbs Iran's nuclear program.
Negotiators reached a framework agreement in March and hope to strike a final deal by June 30.
A fact sheet on the framework accord issued by the US State Department has said Iran would be required to grant the UN nuclear agency access to any "suspicious sites.