North Korea's nuclear capability much stronger than 2006

North Korea's second nuclear test indicated the regime has improved its capacity to some extent since its 2006 attempt. Speculations have been high that North Korea may have produced nuclear warheads that could be carried by its short- and medium-range missiles that can cover all of South Korea and Japan.  David Albright of the Institute for Science and International Security told the Washington Times, “They're not anywhere as good as Israel, but they could probably deploy a weapon on top of a Nodong (Rodong) missile and be fairly confident that it would work.”