A photo of a North Korean long-range rocket in front of the North Korean embassy in Beijing. A nuclear expert said Tuesday he is skeptical of North Korea's capability to produce 100 nuclear bombs by 2020. UPI/Stephen Shaver | License Photo

SEOUL, March 10 (UPI) -- A nuclear arms expert has cast a shadow of doubt over a U.S. researcher's claim that Pyongyang could produce 100 nuclear bombs in the next five years.

In an interview with Voice of America, Olli Heinonen, a former deputy director-general at the International Atomic Energy Agency, said more information about the capability of the nuclear weapons being tested is needed and until then conclusions about the bombs cannot be made.


Yonhap reported Heinonen estimated the current levels of plutonium and enriched uranium in North Korea do not meet the requirements for bomb production.

The nuclear expert said the production of fissure materials and its conversion into a deadly weapon are two different matters.

Heinonen, however, said the bombs could proliferate to a total of 20 in five years, if North Korea is able to produce three or four warheads within a year.

In February, U.S. researcher Joel Wit had said during a seminar in Washington that North Korean scientists could produce 20 to 100 nuclear bombs by 2020.

The Daily Telegraph reported Wit said that North Korea already held 10 to 16 weapons in possession.

On Tuesday an update on the website 38 North said little activity was detected at key nuclear testing sites in North Korea, and tests were unlikely in the future.