While North Korea's claim that it successfully tested a "two-stage thermonuclear weapon" capable of being carried by an intercontinental ballistic missile on Sunday cannot be verified, its latest nuclear test shows once again that the threat posed by its nuclear weapons and ballistic missile programs is increasing as time passes and the international community remains unable to take effective steps to halt the Kim regime's dangerous provocations. This must change.

Pressure on North Korea must be increased and efforts made to close the loopholes that have enabled Pyongyang to mitigate the impact of such efforts and continue its weapons development programs. At the same time, diplomatic efforts directly involving North Korea should be explored to ensure that the worst-case scenario of a military conflict — which would be too costly for countries in the region including Japan — can be averted.

North Korea's claim that it has succeeded in building a miniaturized hydrogen bomb that can be attached to an ICBM has been met with skepticism. But the power of the blast on Sunday, as estimated by the size of temblors caused by the explosion and observed by authorities outside the country, was reportedly several times larger than the last nuclear test conducted by Pyongyang nearly a year ago — and the largest since the regime carried out its first nuclear test in 2006. Chief Cabinet Secretary Yoshihide Suga said the possibility that it was indeed a hydrogen bomb could not be ruled out.