Informed sources in Iran's capital Tehran said that Fordo nuclear enrichment facility will become fully operational over the next few days, the local Mehr news agency reported Sunday.

Iranian President Mahmoud Ahmadinejad said Saturday that Iran will announce new "big" nuclear achievements in days.

"In the following days, the world will witness the inauguration of several big achievements in nuclear fields," he said addressing a large crowd of people gathered at Tehran's Azadi Square on the occasion of the 33rd anniversary of the Islamic revolution.

Early January, Iran's permanent representative to the International Atomic Energy Agency (IAEA) Ali-Asghar Soltanieh said at the IAEA headquarters in Vienna that Iran had begun uranium enrichment at an underground bunker of the Fordo nuclear facility.

The Fordo nuclear plant has been built near the Iranian central Shi'ite holy city of Qom, which was used for producing up to 20 percent enriched uranium.

The start of the nuke work at the Fordo site has increased international fear as the West suspects that Iran's uranium enrichment may be meant for moving closer to the ability to make nuclear weapons. But Iran insists that its nuclear program is only for the purpose of peaceful use.