Akbar Hashemi Rafsanjani, also a former president, said in a sermon to worshippers at Friday prayers broadcast on state radio that U.S. accusations that Iran was diverting its nuclear programme to military purposes were not backed up by evidence.
Washington and its allies accuse Tehran of seeking to build nuclear warheads under cover of a civilian atomic programme, a charge Iran denies, insisting its aim is to generate electricity so it can save more of its vast oil and gas reserves for export.
"We have announced everything. The (International Atomic Energy) Agency (IAEA) has acknowledged … that we have had no diversion," Rafsanjani said.
"But the Americans have raised a claim that we are not announcing everything. Well, a claim of this nature has no limits in scope and anybody can make such a claim in relation to anything. They are not giving any document to support their claim."
The IAEA presented its latest report on Iran on Wednesday, saying the Islamic Republic planned to start installing another 3,000 centrifuges early next year, adding to 3,800 already enriching uranium and another 2,200 being gradually introduced.
The West worries about the enrichment programme because it can have both civilian and military uses.
"As for Mr ElBaradei, whenever he speaks he does it equivocally … (saying) that, for instance, Iran is not letting the agency inspect the Arak heavy water facility," he said, referring to one of Iran's disputed nuclear sites.
"This is again an example of trying to use compulsion in relations to us. We ask the agency to judge neutrally and fairly and avoid speaking equivocally," the former president said.
"We will not let the certain right of a revolutionary and innocent nation be trampled," Rafsanjani added.
The IAEA has been investigating allegations that Iran carried out research into nuclear warheads. The accusations were based on intelligence which came from a laptop computer spirited out of Iran by a defector in 2004 and passed on to Washington, from some other Western states, and from IAEA inquiries.
Iran dismisses the allegations and says U.N. inspectors have access in line with legal requirements to verify what it says is the peaceful nature of the Islamic Republic's plans.
