“Issuing such torn pieces of paper ... will not have an impact on Iranian nation’s will (to obtain nuclear technology),” the semi-official Mehr news agency quoted Ahmadinejad as telling a rally in central Iran.

US, British, French, German, Russian and Chinese diplomats at the United Nations have reached a tentative deal on imposing fresh sanctions on Iran and hope to introduce the measure at the Security Council on Thursday, providing their governments agree.

 An earlier sanctions resolution passed by the Security Council in December was derided by Ahmadinejad in similar terms.

The new measure, which may be adopted next week, would impose extra penalties on Teheran for refusing to suspend uranium enrichment, which can produce fuel for use either in nuclear bombs or civilian power stations.

“What is the aim of issuing such resolutions? Today we are mastering the nuclear fuel cycle completely,” Ahmadinejad said.

“If all of you (Westerners) get together and call your ancestors from hell as well, you will not be able to stop the Iranian nation.”

Western nations suspect Iran’s nuclear programme is a cover for efforts to make atomic weapons. Iran, the world’s fourth largest oil exporter, denies that and says it wants only to supply nuclear power plants.

“The opposite result”

Ahmadinejad said imposing sanctions on Iran would be counter-productive.

“You sanctioned us in the past but we obtained the nuclear technology. Impose economic sanctions on us today and see what would be our next step,” Ahmadinejad said.

Iran’s Supreme Leader Ayatollah Ali Khamenei has the final say in nuclear and other matters. But, like Ahmadinejad, he has also insisted Iran will not give up its atomic plans.

Ahmadinejad said Western powers were wrong to suppose Iran would give up its nuclear programme under political pressure, adding that the Security Council had “no legitimacy”.

“All the Iranian nation insists on this right and will not retreat one iota,” Ahmadinejad said.

Washington says it would prefer a diplomatic solution to the crisis but does not rule out military options.

Iran’s chief nuclear negotiator Ali Larijani warned on Wednesday that Iran would respond militarily if the Islamic state was attacked over its nuclear programme.