Mahmoud Ahmadinejad, the Iranian president, also spoke on the eve of the Geneva talks, saying that his country was prepared to allow a third party to enrich uranium to the grade it requires for its nuclear reactor rather than carry out the enrichment itself.
"One of the subjects on the agenda of this negotiation is how we can get fuel for our Tehran reactor," the president was quoted by ISNA news agency as saying.
"As I said in New York, we need 19.75 per cent-enriched uranium. We said that, and we propose to buy it from anybody who is ready to sell it to us. We are ready to give 3.5 per cent-enriched uranium and then they can enrich it more and deliver to us 19.75 per cent-enriched uranium."
Earlier on Wednesday, Saeed Jalili, Iran's chief nuclear negotiator, said the Islamic Republic would be entering the talks with US, Russia, China, Britain, France and Germany with good intentions.
Jalili described the meeting as an "opportunity and a test" for those attending and said "we are entering the talks with good will".
"Iran's national, regional and international capacities ... could be an opportunity for creating a world based upon peace, justice and progress," he said.
The US and its Western allies have made clear they will focus on Iran's disputed nuclear programme, which they suspect is aimed at making bombs, at the meeting.
On Tuesday, Ali Akbar Salehi, the head of Iran's Atomic Energy Organisation, said "we are not going to discuss anything related to our nuclear rights" at the talks.
Salehi said: "We can discuss about disarmament, we can discuss about non-proliferation and other general issues."
But he ruled out any discussion of the country's second uranium enrichment plant.
"The new site is part of our rights and there is no need to discuss it," Salehi said.
Ministers from the six powers held preparatory talks in Geneva on Wednesday ahead of the meeting with Iran.
Ulrich Wilhelm, a spokesman for Angela Merkel, the German chancellor, said: "Iran is comprehensively failing to co-operate, it is comprehensively failing to live up to its international commitments."
Iran has denied it is developing a nuclear weapon and says it needs nuclear technology to generate electricity.
Tehran has offered wide-ranging talks on security and other issues, but repeatedly ruled out any discussions about its "nuclear rights" at the meeting, the first since Barack Obama, the US president, took office.
|Iran told the IAEA last week that it was building a second plant [AFP/DIGITALGLOBE]
Washington has suggested possible new sanctions on banking and the oil and gas industry if Iran, the world's fifth-largest crude exporter, fails to assuage Western fears it seeks nuclear weapons.
Speaking to Al Jazeera, Martin Navias, a senior research associate at the Centre for Defence Studies in London, said: "I think the Americans and the Europeans by themselves can increase the pain on Iran, there is no question of that.
"They can sanction companies dealing with Iran's import of gasoline products, they can increase the insurance rates and do a number of things by themselves.
"But to make sanctions really effective, really impose costs on the Iranian government, they have to bring the Russians and the Chinese in.
"And I know the Russians have recently been saying that they were more willing to go along with sanctions, but I'm not sure this has any real meaning, and the Chinese, on the other hand, have indicated quite categorically that they want to slow down any talk of sanctions."