SEOUL, South Korea — North Korea is capable of detonating another nuclear device anytime at one of its unused tunnels at the country's main atomic test site, Seoul official said Monday, three days after the country carried out its fifth bomb explosion.



The North's latest nuclear test, the most powerful to date, sparked worries the country is making headway in its push to develop small and sophisticated warheads to be topped on missiles. Seoul, Washington and their allies subsequently vowed to apply more pressure and sanctions on Pyongyang.

South Korea's Defense Ministry spokesman Moon Sang Gyun refused to say what evidence pointed to another possible North Korea test. But he told reporters that South Korea and U.S. intelligence authorities believe North Korea has the ability to detonate another atomic device anytime.





Shortly after the North's test, South Korea's top military intelligence officer, Kim Hwang Rok, said North Korea has two or three unused tunnels in the Punggy-ri test site where it can conduct an additional test if it wants. Kim, director of the Korea Defense Intelligence Agency, made the remarks during a meeting with South Korea's ruling party chief Lee Jung-hyun, according to party spokesman Yeom Dong-yeol.

Also Monday, South Korea's Yonhap news agency, citing unidentified Seoul government sources, reported there were signs the North had finished test preparations in one previously unused tunnel in the Punggy-ri test site.

Yonhap did not provide any evidence or say how the sources got the information.

North Korea's pursuit of missiles and nuclear weapons is one of the most intractable foreign policy problems for the U.S. and South Korea. Diplomacy has so far failed. Six-nation negotiations on dismantling North Korea's nuclear program in exchange for aid were last held in late 2008 and fell apart in early 2009.

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The Korean Peninsula remains technically at war, as the 1950-53 Korean War ended in an armistice, not a peace treaty.