North Korea could produce between 20 to 100 nuclear warheads by 2020 and Pyongyang recently improved its intercontinental ballistic missile, the KN-08, most likely with the aid of Ukrainian engineering, experts said in Seoul on Wednesday. File Photo by James Mossman/USAF | License Photo

SEOUL, Nov. 12 (UPI) -- North Korea could produce 20 to 100 nuclear warheads by 2020, and its latest KN-08 intercontinental ballistic missile was built with technology from the Ukraine, according to experts.

Joel Wit, a visiting scholar at Johns Hopkins University's U.S.-Korea Institute, said Pyongyang was building up its nuclear arsenal and changes in the country would take place gradually, over several generations, South Korean outlet Newsis reported.


Wit also said the current U.S. policy of "strategic patience" toward North Korea has not worked to resolve the nuclear issue, and any hopes of a North Korea collapse would amount to nothing more than "unrealistic magical thinking."

The former U.S. official said it would also be ridiculous to think North Korea's nuclear capacity could be safely secured in the event of a collapse, and the present-day policy of economic sanctions have not had the intended effect of forcing Pyongyang to rethink its nuclear weapons program.

Wit was responsible for implementing key agreements between Washington and Pyongyang during the Clinton administration, including the U.S.-North Korea Agreed Framework to help defuse the crisis in the 1990s.

In an interview with Japan's Jiji Press, Wit said North Korea is most likely to target Japan with its arsenal of nuclear weapons, because Japan plays a crucial role in the defense strategy of the U.S.-Japan alliance.

Speaking at the same seminar on North Korea nuclear issues at the Asan Institute for Policy Studies in Seoul, John Schilling, an aerospace engineer with the Aerospace Corp. in El Segundo, Calif., said the KN-08 intercontinental ballistic missile North Korea unveiled during an anniversary parade on Oct. 10 had a new configuration of two stages, an improvement over the previous missile.

Schilling said North Korea could have relied on Ukrainian engineers in the ICBM redesign, but the Ukrainian government has recently cracked down on the technology transfer to Pyongyang.