Iran's output of enriched uranium has not only been stepped up significantly, but also taken place at a higher enrichment level than required for civil use, recent inspections have shown
United Nations nuclear inspectors have found samples of uranium at Iran's Fordo nuclear processing site which have been enriched to a higher level than Iran admits, according to a report by the nuclear watchdog IAEA.
Iran said it was using the nuclear site to enrich uranium solely for civilian use up to a maximum level of 20%.
However, the UNA inspectors found samples of uranium enriched to 27% - much closer to weapons-grade uranium.
U.S. think-tank the Institute for Science and International Security (ISIS) said that it estimates Iran to have enough uranium for at least five nuclear bombs, subject to further enrichment taking place.
Iran's nuclear program is closely watched by Israel and the West amid concerns Tehran might use the enriched uranium to build nuclear weapons. Iran denied any such plans and insists its aims are entirely peaceful.
Nuclear talks held last week in Baghdad between the six world powers - the United States, Russia, China, Britain, France and Germany - and Iran ended inconclusively after Iran could not be persuaded to scale back its nuclear enrichment program.