The International Atomic Energy Agency (IAEA) regards South Korea's secret research on Plutonium and Uranium as "a matter of serious concern" and will continue probe into the case, IAEA chief Mohamed ElBaradei said Monday.

"It is a matter of serious concern that the conversion and enrichment of uranium and the separation of plutonium were not reported to the agency as required by safeguards agreement," ElBaradei said during a meeting of IAEA governing board.

The IAEA chief said he would report again on the investigation by the board's next meeting in November.

South Korean government admitted last Thursday several scientists secretly extracted a minimal amount of plutonium during a research experiment in 1982.

The acknowledgment came one week after Seoul's announcement that few South Korean researchers conducted enriched uranium separation experiment four years ago.

Source: Xinhua