TODAY | December 13, 2013
>> kim jong un's uncle who was second in command in north korea has been executed. jang song thaek was accused of trying to overthrow the state. andrea mitchell has more from us in washington.
>> reporter: good morning. this is a shake up in the brutal north korean regime setting off alarms in washington and beijing . kim jong un, young and untested. executing his second in command, his own uncle, jang song thaek . the official announcement said he was executed as a traitor calling him despicable human scum, worse than a dog, with the wild ambition to grab the supreme power of our party and state. jang was believed to be in charge of training his nephew to take power. he was also the point man for maintaining the relationship with beijing . earlier this week north korean state tv signalled the downfall by showing him being arrested pulled out of a public meeting. they claim he confessed at a military tribunal . clearly a show trial.
>> it can lead to some sort of instability in the system or collapse or lead to external act of aggression by north korea . a nuclear test or missile test.
>> reporter: tensions remain high since the spring when they threatened south korea and the u.s. and said they would start reproducing nuclear fuel . he recently released an american tourist held since october. but the regime is still holding kenneth bay for more than a year and in the two years since he succeeded his father, kim jong il , he has proved to be erratic bonding with former nba star dennis rodman and spending scarce resources on amusement parks while threatening missile launches. if confirmed this is another example of the extreme brutality of the north korean regime. the white house is monitoring events closely and so is beijing . the chinese have not commented indicating that they're concerned and don't know what to say and there's rising concern about this unpredictable and violent young leader of a nuclear armed nation.
>> incredible story there. thank you so much andrea mitchell . a