Now why would Iran be doing that?

USA Today reports that:

'VIENNA (AP) – Iran has rapidly ramped up production of higher-grade enriched uranium over the last few months, the U.N. nuclear agency said Friday, in a confidential report that feeds concerns about how quickly the Islamic republic could produce an atomic bomb.

The report by the International Atomic Energy Agency also said Iran had failed to give a convincing explanation about a quantity of missing uranium metal. Diplomats say the amount unaccounted for is large enough to be used for experiments in arming a nuclear missile.

Iran insists it is not interested in nuclear weapons and says its activities are meant either to generate energy or to be used for research. But the report contained little assurances the country's activities are purely peaceful.

Instead, it also confirmed that two IAEA missions to Tehran within less than a month had failed to dent Iran's refusal to assist an IAEA probe of suspicions that the country has been secretly working on aspects of a nuclear weapons program.'

Does anybody seriously believe that Iran's nuclear programme is entirely peaceful? If you do, please explan to me, why?