Transcript for Tensions build between US, North Korea

The U.S. Facing tensions with North Korea sending an aircraft carrier strike led by the "Uss Carl Vinson" toward the peninsula. The carrier is over a thousand feet long, has more than 60 aircraft and let's bring in Martha Raddatz. Let's listen to what national security adviser H.R. Mcmaster had to say about the deployment of the carrier strike group. North Korea has been engaged with -- in a pattern of provocative behavior. This is a rogue regime that is now a nuclear capable regime and president XI jinping and president trump agreed that is unacceptable. What must happen is the denuclearization of the Korean peninsula. It does seem to send a strong signal. Reporter: It does. That carrier was originally headed for Australia but this was seen as a prudent move given that North Korea is about to test another nuclear weapon and it continues to make advances in its long-range missile program. This shouldn't be read that the U.S. Is about to make a preemptive strike on those missiles but this does send the message to Kim Jong-un. And the timing is especially relevant given the action we just took in Syria and the fact that China's president was just in those meetings with president trump where they both agreed that North Korea's behavior has to change, robin. Let's turn back to Syria for a moment because we heard the secretary of state talking with George over the weekend and he pretty much said it's up to the people of Syria to decide the fate of their president, president Assad but then you have Nikki Haley seeming to take a more forceful stance and said we have to make sure we see a leader who will protect his people and Assad is not it. Bit of a mixed signal. Reporter: You know, I think these statements seem to send different signals and yet I don't think you can parse the words of this administration in the same way as previous administrations or you can assume at this early point they have an overall strategic policy there but in this case I would listen to Rex tillerson who seems to be saying again that getting Assad out is not the priority here and if you look closely at Haley's comments she's not saying getting him out is the responsibility of the U.S. They want to push him but rather what the administration wants to see happen, robin. Good points as always, thank you, Martha. Tillerson clear on no change in military strategy right now in Syria.

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