Iran's President Mahmoud Ahmadinejad yesterday rejected a Western proposal for it to "freeze" its nuclear work in return for no new sanctions and ruled out any talks with major powers on the issue.
The comments by the President, who is seeking a second term in a 12 June election, are likely to further disappoint the US administration of President Barack Obama, which is seeking to engage Iran diplomatically.
The United States, Russia, China, France, Germany and Britain said in April they would invite Iran to a meeting to try to find a diplomatic solution to the nuclear row.
The West accuses Iran of secretly developing atomic weapons. Iran, the world's fifth-largest oil exporter, denies the charge and says it only wants nuclear power to generate electricity.
Breaking with past US policy of shunning direct talks with Iran, President Obama's administration last month said it would join nuclear discussions with Tehran from now on. Mr Ahmadinejad proposed a debate with Mr Obama at the UN in New York "regarding the roots of world problems" but he made clear Tehran would not bow to pressure on the nuclear issue. "Our talks will only be in the framework of co-operation for managing global issues and nothing else. We have clearly announced this," Mr Ahmadinejad said.
"The nuclear issue is a finished issue for us," he told a news conference. "From now on we will continue our path in the framework of the [UN nuclear watchdog] agency."
He was asked about a so-called "freeze-for-freeze" proposal first put forward last year under which Iran would freeze expansion of its nuclear programme in return for the UN Security Council halting further sanctions against Tehran. Western diplomats say the proposal remains on the table.
Mr Ahmadinejad, facing a challenge in the election from moderates advocating détente with the West, has made angry rhetoric against the US and its allies his trademark since he came to power in 2005.