"Today the agency is announcing that the production capacity is increasing dramatically of the 60% inventory," Reuters quoted Grossi who was speaking on the sidelines of the Manama Dialogue security conference in Bahrain.

He said that Iran's production capacity was set to rise to seven, eight times more, maybe, or even more than the current level of 5-7 kg of uranium enriched to up to 60% purity a month.

Reuters also claimed to have seen a confidential report to IAEA member states, which said Iran had increased enriching uranium to up to 60% at its Natanz and Fordow sites.

The report claimed that Iran had increased the enrichment rate of the material to feed them into two interconnected cascades of advanced IR-6 centrifuges at Fordow.

Western countries accuse Iran of trying to build nuclear weapons. Iran rejects that, saying it wants nuclear energy to meet its domestic needs.

In response to a recent anti-Tehran resolution by the IAEA's Board of Governors, Iran has started the activation of the advanced centrifuges.

In a related development, Mohammad Eslami, the head of the Atomic Energy Organization of Iran (AEOI), has said that the country’s nuclear program is fully transparent and for peaceful purposes.

The Islamic Republic has always demonstrated that it is willing to engage in interaction; meanwhile, the country will not forfeit its rights in the face of pressure, illegitimate behavior, and bullying, the AEOI head said.