"The latest level of enrichment carried out in Iran has been 4.8 percent. Enrichment of more than five percent is not on Iran's agenda and this level suffices for making nuclear fuel," ISNA quoted Gholam Reza Aghazadeh as saying.

The process of enriching uranium though cascades of centrifuges lies at the centre of international concerns about Iran's nuclear programme.

When extended to much higher levels of purity, it can produce the fissile core of an atom bomb, although Iran insists it is only interested in producing fuel for civilian nuclear reactors.