Iran's president has promised to disclose news about Iran's nuclear program when he visits its uranium enrichment facility on Monday where the West says Iran is mastering the skills needed to make atomic bombs.

Iran has rejected U.N. demands to halt enrichment, a process than can make power plant fuel or material for warheads, and has instead vowed to expand what it insists is peaceful atomic work.

Diplomats speculate President Mahmoud Ahmadinejad could announce that Iran has installed more centrifuges, the machines used in the enrichment process, at the Natanz facility in central Iran. But Iranian officials have been tightlipped.

"If you wait 24 hours, you will all find out," Foreign Ministry spokesman Mohammad Ali Hosseini told a Sunday news conference when asked what the president would announce.

Journalists will accompany the president with senior officials from Iran's Atomic Energy Organization to the site about 200 km (125 miles) south of Tehran.

Ahmadinejad, who said in February he would announce "great" nuclear achievements in the days to April 9, is expected to hold a news conference.

Sunday's Jam-e Jam newspaper wrote: "The installation and start up of 3,000 centrifuges and the injection of uranium hexafluoride (UF6) gas will be announced by the president."

UF6 gas is fed into centrifuges as feedstock.

Iran, the world's fourth largest oil exporter which says it wants a network of nuclear power plants, runs 350 experimental centrifuges at an above ground pilot facility at Natanz.

The IAEA said in February Iran had set up two cascades of 164 centrifuges below ground, where Iran is installing 3,000 machines as part of its "industrial" enrichment plans.

Diplomats who follow Iran's nuclear file say Iran has set up four more cascades since February, bringing the total number now in the underground section to six cascades or 984 centrifuges. The diplomats have said no feedstock has been fed in yet.

The Islamic Republic's refusal to accept U.N. demands to stop enrichment has prompted the U.N. Security Council to pass two sanctions resolutions on the country since December.

The UN's nuclear watchdog, the International Atomic Energy Agency, says it has gaps in its knowledge about Iran's plans that need to be filled before it can confirm they are peaceful.

The IAEA is pushing Tehran to agree to let it install cameras in the underground section of Natanz to monitor Iran's work. Iran says such intrusive surveillance goes beyond its basic safeguards commitment to the IAEA. Talks continue.

Angered by the second sanctions resolution in March, Iran said it would limit cooperation with the IAEA by not giving early word of plans to build new nuclear installations, backing out of a voluntary agreement to provide such information.