Secretary-General Ban Ki-moon speaks on Iran's nuclear issue at a news briefing at UN headquarters in New York, the United States, Sept. 29. 2009. Ban Ki-moon said that he had told Iranian President Mahmoud Ahmadinejad during their Friday meeting that Tehran should have revealed the "secret" uranium enrichment facility earlier and should give full access to the International Atomic Energy Agency (IAEA). (Xinhua/Shen Hong) Photo Gallery>>>

    UNITED NATIONS, Sept. 29 (Xinhua) -- UN Secretary-General Ban Ki-moon told Iranian President Mahmoud Ahmadinejad during their Friday meeting that Tehran should have revealed the "secret" uranium enrichment facility earlier, the secretary-general said at a press briefing here on Tuesday.

    "This new uranium enrichment facility is contrary to Security Council resolutions," he said. "They should have made all the processes in a transparent way and they should..give full access to the International Atomic Energy Agency (IAEA). This is what I told him."

    In a statement attributable to Ahmadinejad made public Monday night, the Iranian president lambasted Ban for jumping to conclusion before the IAEA had even begun inspecting the uranium facility.

    "It is of grave concern that the UN secretary-general, instead of waiting for the IAEA, as the competent body to reflect on this issue, namely the new enrichment facility, has chosen to repeat the same allegations that few Western powers are making," said the statement.

Secretary-General Ban Ki-moon speaks on Iran's nuclear issue at a news briefing at UN headquarters in New York, the United States, Sept. 29. 2009.(Xinhua/Shen Hong) Photo Gallery>>>

     But Ban defended his position, saying that it was a question of timing.

    "This is a question of when you should inform of the existence of such facilities," he said. "When (they) had the intent, they should have informed the IAEA a long time before, not just before everything is completed. There is a question of transparency."

    Speaking at the G20 summit, U.S. President Barack Obama, British Prime Minister Gordon Brown and French President Nicolas Sarkozy called the second plant as proof of Tehran's intention to beguile the world and violate international norms.

    Ahmadinejad called the allegations of concealment baseless and said "Iran has gone far beyond its treaty obligations by informing the Agency 12 months sooner than the timing it is legally required to do so."

    "Iran has acted with utmost transparency in this regard and it should be encouraged for having done so instead of being unfairly criticized," the statement added.

    On Sept. 21, Iran informed the IAEA that it was building "a new pilot fuel enrichment plant" inside a mountain south of Tehran.

    In response, the IAEA has requested specific information and access to the facility as soon as possible.

    Reiterating past comments, Ban said "the burden of proof is on Iran" to demonstrate the country's nuclear program is for peaceful purposes.

    Later on Tuesday, Ban will meet with Iranian Foreign Minister Manouchehr Mottaki as part of "ongoing efforts to bridge the gap and urge them to fully cooperate to resolve all pending issues nuclear, humanitarian and human rights."

    A delegation from Tehran is expected to discuss the nuclear issue on Thursday with the permanent five members of the Security Council -- Britain, China, France, Russia and the United States --and Germany.

    Depending on the meeting's outcome, Iran -- the world's fourth-largest oil producer --faces possible economic sanctions, including restrictions on banking and on oil and gas technology.