The shock warnings come as President Donald Trump begins his extensive trip around Asia to reassure allies about his commitment to defending them against North Korea.
According to Harry Kazianis, a North Korean security expert, the American intelligence experts believe that Kim Jong-Un has everything he needs to launch strikes on the US.
Speaking to Fox News, Mr Kazianis said the speed of the escalating North Korean threat had shocked even those most familiar with the communist regime.
Mr Kazianis, who serves at the Centre for the National Interest, said that the belief that North Korea would only gain the capability to nuke the US by next year was wishful thinking.
He explained: “I will be honest, I think they can do it right now. They have all the technological pieces they need to do it.
“They have long-range missiles, they can miniaturise warheads to put on the missiles, and top sources at the Pentagon have told me they have the tracking to do it .
“I say we are out of time, it is a case of when – not if- now. It’s only a question containing North Korea.
“This is a threat we did not see coming. Many believed they were still 2-3 years off from developing ICBM.”
The chilling warning comes after the US Joint Chiefs admitted that ground invasion was the “only way” to totally destroy all parts of North Korea’s nuclear weapons programme.
The Pentagon assessment mentioned the possibility that chemical and biological weapons might be used by the regime.
They revealed the ensuing conflict “could result in hundreds of thousands or even millions of deaths in just the first few days of fighting.”
In response, Mr Kazianis said that the US had to stop “playing nice” with China and exert control over its pressure points.
He said even a small push of robust sanctions would “strangle” the North Korean economy and leave the regime out of power and fuel.