The International Atomic Energy Agency has said that Iran has started the next stage toward building a nuclear bomb. The IAEA says the Islamic state has developed a second set of centrifuges, which can enrich uranium to the 20 per cent threshhold which experts fear can be turned into weapons-grade material. If enriched to around 95 percent, uranium can be used in building an atomic bomb. Tehran insists its nuclear activities are for peaceful purposes only. Sadegh Zibakalam, a Tehran-based professor of political science says the international community has no grounds for concern over Iran's nuclear developments.