Vienna:
Talks in Vienna aimed at persuading Iran to move most of its enriched uranium out of the country got off to a "good start", the head of the UN nuclear agency said on Monday.
The comments by Mohamed ElBaradei, who heads the International Atomic Energy Agency, were significant because Iran had earlier signalled it would not meet Western demands for a deal under which it would send most of its enriched material abroad, a move that would delay its ability to make a nuclear bomb.
Tehran has said it needs enriched uranium for nuclear fuel, but the West fears it could be used to make weapons, and the US says Iran is now one to six years away from being able to do so.
Monday's talks between Iran and the US, Russia and France were focused on a technical issue with huge strategic ramifications - whether Iran is ready to farm out some of its uranium enrichment programme to a foreign country.
ElBaradei appeared cautiously optimistic after the first day of closed meetings, saying most technical issues had been discussed and the parties would meet again Tuesday morning.
The delegations said little as they left the talks. The chief Iranian delegate, Ali Asghar Soltanieh, said only that he endorsed ElBaradei's comments.
Iranian agreement to ship out most of its enriched uranium would be significant because 1,000 kilograms (2,205 pounds) is the commonly accepted threshold of the amount of low-enriched uranium needed for production of weapons-grade uranium enriched to levels above 90 percent.
Iran's state-run Press TV cited unnamed officials in Tehran as saying the Islamic Republic was looking to keep its low-enriched uranium and buy what it needed for the Tehran reactor abroad.
One source said Iran was looking to the US, Russia or France for such supplies.
Such a stance would likely doom the talks, with neither the US or France accepting such terms.
Tehran's refusal to give up most of its enriched stock could also abort chances of a second round of broader negotiations between Iran and six world powers on the Islamic Republic's nuclear programme.