South Korean Defense Minister Song Young-moo speculates North Korea has secured a significant ability to develop miniaturized nuclear warheads.  

While briefing the parliament’s national defense committee on Monday, Song said the ministry agrees with the view of Representative Kim Jin-pyo of the ruling Democratic Party that North Korea's recent sixth nuclear test has equipped the regime with the capability to make a nuclear warhead weighing less than 500 kilograms.

Song added the smaller a nuclear bomb is, the more effective it is.

Asked about his judgement on whether the North has completed its program to miniaturize nuclear warheads, Song said he thinks the North has seen progress enough to mount a nuclear warhead on an ICBM.