'100 years' of resolutions would not change nuclear programme, warns Ahmadinejad.
Iran vowed on Saturday to retaliate if the UN Security Council imposes new sanctions after the latest UN atomic agency report on its nuclear activities spoke of progress.
And ahead of a meeting of major powers on Monday to discuss a new draft package of sanctions, Iranian leaders insisted that more UN resolutions would be pointless and without legal basis.
"They could spend 100 years passing resolutions but it wouldn't change anything," Iranian President Mahmoud Ahmadinejad said in an interview with state television.
"We have prepared plans if they continue. Any country that leads the way, European or non-European, must know that we will take firm reprisals," Ahmadinejad said.
He insisted it was "in the interest" of the world's major powers to change their attitude towards Iran, adding that Iran was "not joking."
He dubbed the report by the Vienna-based International Atomic Energy Agency (IAEA) as a "historic victory of Iran in its greatest confrontation with the oppressive powers since the Islamic revolution" of 1979.
Javad Vaidi, deputy head of Iran's Supreme National Security Council, said that "if the Security Council wants to issue a resolution it will be legally and technically baseless," ISNA news agency reported.
The UN watchdog said it had made "quite good progress" in its long-running probe into Iran's contested nuclear drive, but that Tehran was still defying UN demands to halt uranium enrichment.
The IAEA's report on Friday came amid a new push by Western powers for a third package of UN Security Council sanctions against Tehran, which diplomats in New York said could be agreed as early as next week.
The UN agency said it was still not in a position to determine the "full nature of Iran's nuclear programme" which the West fears could be cover for a drive to make nuclear weapons.
The UN ambassadors of Britain and France have formally introduced to the Security Council the draft of a new resolution imposing fresh sanctions.
The draft would impose a travel ban on officials involved in Tehran's nuclear and missile programmes and inspections of shipments to and from Iran if there are suspicions they may contain prohibited goods.
The draft text also calls "upon states to exercise vigilance in entering into new commitments for public-provided financial support for trade with Iran, including the granting of export credits, guarantees or insurance to their nationals involved in such trade."
Washington plans to host talks in the US capital on Monday with diplomats of the six powers -- the five veto-wielding Security Council permanent members plus Germany - to review the draft.
But Iran's government spokesman Gholam Hossein Elham said it was "illegal and unjustifiable to keep Iran's nuclear case at the Security Council," vowing that "it will not affect the country's will" to pursue its nuclear programme.
Iran is already under two sets of UN Security Council sanctions for its failure to heed repeated Security Council ultimatums to suspend uranium enrichment.
It insists that as a signatory to the nuclear Non-Proliferation Treaty it has a right to make enriched fuel to meet its population's growing energy needs.
The IAEA said nearly all of the key issues agreed in the so-called "work plan" drawn up by the UN watchdog and Tehran last autumn had been resolved.
However, one crucial issue was still outstanding - Iran's alleged work in missile and explosives experiments which could point to a possible military dimension to its nuclear ambitions.
The IAEA also complained that Iran had begun development of new generation centrifuges for uranium enrichment - the process which can make nuclear fuel or, in highly extended form, the fissile core of an atomic bomb.
Israel, the sole if undeclared nuclear-armed state in the Middle East, meanwhile said it supports new sanctions on Iran which it views as its greatest threat.
"The fact that the International Atomic Energy Agency admits in its report that it was not able to determine the true nature of the Iranian nuclear programme is very serious," Israeli government spokesman Avi Pazner said.