North Korea appears to have taken yet another major step in showing off its nuclear prowess, developing a miniature nuclear warhead.
US President Donald Trump has responded to the news saying: "North Korea best not make any more threats to the United States.
"They will be met with fire, fury and frankly power the likes of which this world has never seen before."
US nuclear researcher Melissa Hanham told Morning Report Mr Trump would have just learnt the information from news sources and he is being reactive.
"It's very untraditional for an American President to put out a statement like that. First because you would want to follow up an public statement with some kind of enforceable action that would happen afterwards. Second, you'd want to be advised by your intel community."