The Yomiuri Shimbun said it learned of the warning from Jang Song Thaek from an expert on North Korea in Macao, the South Korean Yonhap news agency said. Jang is married to the sister of the late Kim Jong Il and is thus the uncle by marriage of both Kim Jong Un and his brother, Kim Jong Nam.
Kim Jong Nam is a shadowy figure, believed to be in his 40s and to be living in Macao, a former Portuguese colony that is now a semiautonomous part of China. His younger brother succeeded to the leadership of North Korea when his father died last year, 17 years after succeeding his father, Kim Il Sung.
"It is difficult to accept a third-generation succession under a normal reasoning," he said.