Kim Jong Un too 'young and impulsive': South Korean Defense Minister

Singapore (CNN)  Young, rash and impulsive. A frank assessment of North Korean leader Kim Jong Un by South Korean Defense Minister Han Minkoo. Speaking exclusively to CNN on the sidelines of a defense forum in Singapore, Han says it's a combination that concerns him greatly. "Kim Jong Un was just 28 when he came to power with very little time to prepare. Add to that, he is very young, he lacks experience."

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Nuclear threat

Kim certainly seems to be in a rush to perfect his nuclear and missile capabilities, the intensity of testing this year alone is unusual even for North Korea.

"If you look at his father, Kim Jong Il, during his 18 year reign, there were about 18 missile tests. During Kim Jong Un's four year reign there (have been) 25 missile tests," says Han.

Han is not convinced North Korea can miniaturize nuclear weapons or fit a nuclear warhead onto a missile, as claimed by Pyongyang, but acknowledges that practice makes perfect.

"If they continue to progress with the miniaturization technology, we think it may be possible to deliver it in other ways such as an artillery shell or in the form of a nuclear mine."

At the recent Workers' Party Congress, Kim Jong Un made it clear North Korea is a nuclear power and will remain one, a statement Washington and Seoul cannot accept.

"South Korea, the United States and other countries will never acknowledge a nuclear North Korea. Therefore, we have to reassure this action and keep pressuring to make denuclearization possible," Han says.

Han and other South Korean officials believe the recent round of U.N. sanctions is the way to do that. They hope the sanctions can force Kim Jong Un's hand and convince him to give up part of his state ideology, a cornerstone of his leadership that he believes his very survival depends on.

When asked if this denuclearization would be peaceful, Han answered simply, "we have to work to ensure it's peaceful."

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Missile defenses

From completing his military service more than forty years ago to becoming Minister of Defense, North Korea has never been far from Han Minkoo's mind. The two Koreas are still technically at war as no peace treaty was signed after the Korean War, only an armistice.

Pyongyang's recent offers of military talks with the South are simply a ploy, says Han.

"The world knows North Korea's nuclear and missile program ignores non-proliferation and international norms and threatens the peace and stability of the Korean peninsula ... North Korea needs to show a sincere will to denuclearize and bring this to the negotiating table."

U.S., allies prepare to face North Korean missiles 02:03

North Korean-born sons of U.S. defector appear in propaganda video

Seoul's top military officer does admit there are limitations in its ability to defend itself from the North Korean threat, claiming the U.S. missile defense system THAAD is the way to close that gap.

U.S. and South Korean officials have been in talks in recent months to decide potential deployment locations, procedure and cost sharing.

Han says from a military point of view, THAAD is necessary to protect South Korea.

"The whole world knows about North Korea's missile capabilities, ranging from short to mid to long range and some they are still developing," he says. "South Korea only has the capacity to intercept a missile at its terminal phase so we have limitations."

As for China's vocal opposition to more U.S. military hardware being deployed in northeast Asia, Han says he'd welcome experts and technicians to come and take a look at the equipment and see its technical specifications and make up their own mind.

"It is important for South Korea and the U.S. to strengthen and promote strategic communications with China."