N Korea: 'News comes as a shock to us in South Korea'
13 December 2013 Last updated at 05:03 GMT
The once-powerful uncle of North Korean leader Kim Jong-un has been executed after being purged for corruption, state news agency KCNA reports.
Chang Song-thaek was dramatically removed from a Communist Party session by armed guards earlier this week.
Professor Jung-Hoon Lee told BBC News that the news "comes as a shock".