I don't know if UN has responded this situation right now, since its general secretary is a Korean, Ban Ki-moon. Its could be a trigger for World War III if no country can't calm this situation down.
There won't be WWIII over Korean border. The last Korean war didn't do it and so won't the next. Kim is childish but not suicidal, he's just marking his territory.
But everything could happen, its because like you said, Kim is childish. I'm not sure all nukes and other weapons he has prepared just for Korean war.
i hope this war can be stoped.
what the trigger from the two country,
i have watching Korea Drama The King Two Heart. mat be north Korea and SOuth Korea, and take this to learning,
from this Drama we know is South Korea dont want to have hostile with South korea.
whats gonna we can do bring to 2 countys if they is manipulate from the country SUPER POWER in this earth?
I'm not sure a drama could change Kim Jong-Un mind, and I think there is no manipulating in this situation. Its just a pride problem between both country.