Iran has accelerated uranium production and enrichment and has already accumulated the resources to create several nuclear warheads. Director General of the International Atomic Energy Agency Rafael Grossi said this in a commentary to Bloomberg.

He noted that the IAEA inspectors believe that Tehran now has enough highly enriched uranium to create several nuclear warheads. 

"It's a very frustrating cycle. We don't understand why they are not providing the necessary transparency," Grossi said.

The head of the agency emphasized that the inspectors did not find any diversion of Iran's uranium stockpile to weapons, but the production and storage of such a large amount of material is a cause for concern.