Transcript for North Korea threatens missile strike on Guam

They defied president trump with a new threat against Guam. That came hours after the president warned that any new threats from North Korea would be met by fire and fury. You know, that blistering rhetoric is a real break from pa presidents and it is being met with concern from Republican and democratic lawmakers as the new poll shows that six out of ten Americans are uneasy about president trump's ability to handle North Korea. Our chief global affairs anchor Martha Raddatz starts us off. Good morning. Reporter: Good morning. The trump administration has always said a military option with North Korea remains on the table but as a last resort. But these words from president trump did not make it sound that way. After the president, the dramatic escalation. North Korea best not make any more threats to the united States. They will be met with fire and fury. Reporter: And one U.S. Territory just over 2,000 miles away from North Korea in the crosshairs. Overnight, the small pacific island of Guam home to crucial American military bases and more than 7,000 U.S. Forces on alert after North Korea said in a statement its leaders are seriously considering a plan to target the territory with missiles. An attack or threat on Guam is a threat or attack on the United States. Reporter: This after that stunning warning from president trump who north Korean leader Kim Jong-un yesterday. He has been very threatening beyond a Normal statement and as I said, they will be met with fire, fury and, frankly, power, the likes of which this world has never seen before. Reporter: An overt military threat, all the more alarming given the latest extraordinary intelligence assessments of North Korea's nuclear capabilities. U.S. Analysts now believe the country can produce miniature nuclear warheads like the one Kim Jong-un posed next to last March claiming then it was, indeed, a miniature nuke. Those warheads able to fit inside icbm missiles that Kim launched twice last month, the last traveling farther than ever before. This morning some political leaders even from the president's own party concerned that the commander in chief's fiery warnings could further incite the already volatile north Korean leader. You got to be sure that you can do what you say you're going to do. The great leaders that I have seen, they don't threaten unless they're ready to act. Reporter: And, of course, this war of words is all the more worrisome given that intelligence report on the north's capable, George. Martha, you mentioned the miniaturization of the nuclear warheads. That's not the only alarming news in there. Reporter: It isn't. Intelligence has estimated from a couple to several dozen nuclear weapons in North Korea but this latest report puts the number at 60, the highest we have ever heard and the most definitive, George. Their program accelerating so quickly, Martha Raddatz, thanks very much. Thank you, George. We'll talk more about it. Joining us is our contributor retired colonel Steve ganyard. So tell us what is the possible threat to the U.S. Well, robin, what happened yesterday was the U.S. Intelligence committee -- community finally said we think they can miniaturize one of these weapons to put on a rocket that will get all the way to the United States. So take a look at this video here. This is the evolution of how long these missiles and how far they've been able to reach over time. This is why the north Korean threat has become so much more serious because they've finally developed those kinds of weapons that can reach all the way to the continental United States. Some people even believe that he can reach somewhere out here maybe as far as the east coast of the United States. What are America's options here? Well, robin, we have what's called a ground-based interceptor and that is a ballistic missile system that is able to -- is able to reach up like a rocket and be able to get into space and intercept these north Korean missiles as they come in to -- towards the united States so the whole idea is we have this developing system. It's a technological marvel but only at a 50% rate of success so we need to protect the continental United States. Steve, you have served in the state department so you know about the diplomatic side of things and what is your take on the words, the language that president trump is using with this? Robin, this is really the first kind of fiery rhetoric we've seen out of a U.S. President since really Harry Truman and so the president has made the decision to make a direct video appeal to Kim Jong-un to make him understand what the U.S.' response will be. The question is does this ramp up, does it continue to ramp up or do things begin to calm down? The next few days will be critical. Steve, thank you.

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