John Bolton, who served under George W Bush, said: “The issue is, is there a way to go after the facilities that we know about and destroy them.
“I think that is entirely doable. The problem is that any use of force against North Korea such as a targeted assassination of Kim Jong-un , the use of special operatives or cyber warfare could trigger a North Korean retaliation against South Korea.
“That is what people are most worried about and legitimately so.”
“You have to look at in a very cold and objective way because the threat to the America people of North Korea not only having this capability itself but selling it to others – selling it to Iran and terrorist groups.
“Kim Jong-un knows that if war breaks out, he is probably one of the first casualties.
“So having a nuclear deterrent is something Kim Jong-un understands in his calculus, trying to survive.”
In November Donald Trump officially declared North Korea was back on the US’ watch list for state sponsored terrorism which includes Iran – designated in 1984, Sudan – added in 1993, and Syria – listed in 1979.
The announcement came after a United Nations report revealed that North Korean weapons were discovered on Iranian ships on route to war-torn Somalia.
According to the report, the Iranian ship was smuggling machine guns from North Korea to arm militants in Somalia and Libya.
A UN diplomat earlier asked: “Why are Iranian and North Korean small arms finding their way into Somalia from Libya? Do they date from before the arms embargoes against both North Korea and Iran? How did they get there from Libya?
“It certainly emphasises the point that Somalia is a country awash with arms and still very fragile.”
Earlier this year a North Korean ship was also seized after it was caught carrying a huge supply of weapons to Egypt.
More than 30,000 rocket-propelled grenades discovered on board the freighter named the Jie Shun which the hermit kingdom had decorated with deceptive Cambodian colours.
The rogue state has made no secret of its plans to develop a nuclear-tipped missile capable of hitting the US mainland and has fired two missiles over Japan in the second half of this year.
On September 3 North Korea detonated its sixth and largest nuclear test, which sparked an artificial earthquake with a magnitude of 6.3.