The United States, Russia and France on Wednesday formally responded to Iran's new fuel deal proposal, diplomats said in Vienna, hours before the UN Security Council was scheduled to vote on a new set of sanctions against the Islamic state, DPA reported.
One diplomat, who spoke on condition of anonymity, said the reply likely contained concerns by the three countries over Iran's plan, which has the support of Turkey and Brazil.
Under the proposal, Russia and France would make nuclear fuel for a medical-use research reactor in Tehran. In return, Iran would place about half of its current stock of low-enriched uranium in storage in Turkey.
The answer was conveyed to Iran through International Atomic Energy Agency (IAEA) chief Yukiya Amano in Vienna.
The US, Russia and France originally offered a similar deal last October, but had asked that the low-enriched uranium be delivered to them directly so that it can be turned into fuel.
US officials have said that the situation had changed since last October, because Iran has since boosted its enrichment levels to 20 per cent. It has also produced more enriched uranium stock, diminishing the value of the confidence-building gesture of shipping out 1,200 kilogrammes of this material.
While mulling their answer since Iran handed in its proposal on May 24, world powers have also drawn up new sanctions in reaction to Iran's progressing nuclear programme and its reluctance to talk to the IAEA about alleged nuclear weapons work.