The symbolism was obvious: a rally that celebrated Iran's nuclear program was held outside the old U.S. Embassy where student radicals took American diplomats hostage in 1979.
Nearly thirty years after that painful episode for the United States, Iranian demonstrators shouted down the idea of U.S.-led sanctions over Iran's nuclear ambitions.
Behind the scenes, there was no shouting, but the message was loud and clear.
In an exclusive interview with CBS News correspondent Elizabeth Palmer, Dr. Ali Larijani – the head of Iran's national security council and the country's chief negotiator on nuclear issues – said now that Iran has succeeded in enriching uranium, there will be no turning back.
"This is a whole new ball game and requires a new solution," said Larijani, asked what incentives could be provided to persuade Iran to abandon its nuclear program. "We cannot insist on the solutions of the past."
The dispute over Iran's nuclear plans centers on what is happening in a nuclear plant in the town of Natanz, where three weeks ago, Iran managed to enrich uranium using sophisticated centrifuge technology.
Iran insists its intentions are peaceful - and the uranium is only to make fuel for nuclear power plants.
The problem is that in concentrated form – the same substance can be used to make nuclear weapons.
"Is there anything the West could offer you to suspend enrichment indefinitely?" asked Palmer.
"Why do you insist on that line of questioning?" said a visibly exasperated Larijani. "They [U.S. officials] want us to develop - in his excellency's words - amnesia vis a vis enrichment to completely give it up."
"So you're saying you won't do it?" asked Palmer.
"No ma'am," said Larijani, standing firm.
A worried United Nations had ordered Iran to suspend its uranium enrichment program by last Friday - but Iran refused, saying that at the least, it will maintain a small scale, experimental enrichment program.
Palmer: "So you would be happy with just a pilot program?"
Larijani: "Yes, for Rand D, a pilot program will do."
Palmer: "How many centrifuges do you need?"
Larijani: "I have learned not to interfere in the workings of engineers. This has a scientific explanation… in my interview with CBS's reporter I cannot talk about the exact number of centrifuges."
Iran has set conditions it knows the U.S. will not accept. The Security Council members meeting in paris Tuesday will have a lot to talk about – as the really tough negotiations begin.
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