We turn overseas now and to an abc news exclusive. One-on-one with secretary of state john kerry, reacting to what we watched unfold in north korea this week. The young leader consolidating power,... See More
We turn overseas now and to an abc news exclusive. One-on-one with secretary of state john kerry, reacting to what we watched unfold in north korea this week. The young leader consolidating power, taking aim at his uncle. A former mentoring. Air brushing him out and executing him. Martha raddatz traveling in the region with new reaction from secretary kerry. Reporter: Good evening. The diplomatic tour brought him here to vietnam where we asked about the startling developments out of north korea where kim jong-un, the leader, had his uncle executed. A long-time power broker in the secretive nation. What does this tell you about the danger coming from north korea? It tells us how ruthless and reckless he is. It tells us about how insecure he is. This is not first execution. There have been a significant number of executions taking place over the last months which we're aware of. Reporter: And this was so public. It really reminded me of a video we saw of saddam hussein doing the same thing. Having people plucked out of an audience. And people sitting there sweating and nobody daring to move or do anything. Reporter: We also asked the secretary about robert levinson who disappeared in iran seven years ago. His family said he was working for the cia and the government has now abandoned him. So suggest that we've abandoned him or anybody has abandoned him is simply incorrect. The fact is that I have personally raised the issue not only at the highest level that i have been involved with but also through other intermediaries. Reporter: Secretary kerry think says he thinks the iranen government could help in this situation and hopes the government will. David. Thank y and martha will have much more of the exclusive interview first thing in the morning on abc's this week.
This transcript has been automatically generated and may not be 100% accurate.