General Hossein Salami, the Guard's deputy leader, said on Sunday on state TV that allowing the foreign inspection of military sites is tantamount to "selling out."
Iran and six world powers have reached a framework agreement to curb Tehran's nuclear program in return for lifting sanctions, and hope to strike a final deal by 30 June.
A fact sheet on the framework accord issued by the State Department said Iran would be required to grant the UN nuclear agency access to any "suspicious sites."
Iran, which insists its nuclear programme is for purely peaceful purposes, has repeatedly said its military sites will not be open to inspection.