New York  - United Nations General-Secretary Ban Ki-moon told Iranian President Mahmoud Ahmadinejad at a meeting in New York on Friday that he is very concerned about Iran's enrichment of uranium, the UN said in a statement.

Ban repeated his demand that Iran must implement the UN Security Council's resolutions and cooperate fully with the International Atomic Energy Agency.

He also said that constructive talks must begin as soon as possible.

On Friday, Tehran unexpectedly admitted that it was operating a second uranium enrichment plant. It had been thought that Iran only had one enrichment facility in Natanz. (dpa)