Iranian President Mahmoud Ahmadinejad warned on Tuesday that a nuclear swap deal brokered by Turkey and Brazil was a one-time opportunity.
He also cautioned the UN security council against imposing new sanctions on the country.
Mr Ahmadinejad said at the Asian security summit that new sanctions would be a mistake and that President Barack Obama stands to lose unless he changes his policies toward Iran.
The leaders of Iran, Turkey and Brazil met in Tehran last month and proposed a deal for Iran to deposit 2,645lb of lightly enriched uranium in Turkey in exchange for 120kg of fuel that it can use for its research reactor.
US officials have criticised the agreement, calling it a ploy by Iran to delay new international sanctions.
But Turkey and Brazil, both non-permanent members of the security council, are now pressing for an open "political debate" on the broader Iranian nuclear issue before a vote on new sanctions.
"The meeting in Tehran created an opportunity for the US administration and for its allies and we still hope that they will be able to use this opportunity," said Mr Ahmadinejad.
"We say that this opportunity will not be repeated."
The security council is expected to vote soon on a resolution which would ban Iran from pursuing "any activity related to ballistic missiles capable of delivering nuclear weapons," bar Iranian investment in activities such as uranium mining and prohibit Iran from buying several categories of heavy weapons including attack helicopters and missiles.
But Russian Prime Minister Vladimir Putin called for any sanctions to be restrained.
"Russia is not of the opinion that these resolutions should be excessive and put Iran and the Iranian leadership - not to mention the Iranian people - in an awkward position that would place barriers in the way of peaceful atomic energy," he said.
Mr Putin also announced that the Bushehr nuclear power plant, which Russia is constructing for Iran, should come online by August.
Hours earlier, Mr Ahmedinejad had warned Russia against supporting new sanctions on his country.
"They must be careful not to side with enemies of the Iranian nation," he said. "They should make a choice."
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