The youngest son of North Korean leader Kim Jong-il has been appointed to two key party posts, in a move widely seen as part of a gradual transfer of power. State media said Kim Jong-un was named vice-chairman of the Central Military Commission of the ruling Workers' Party, which is holding a rare meeting. He was also appointed to the party's central committee. Earlier, the younger Mr Kim was made a general. His father was re-elected as leader but is thought to be in poor health. Kim Jong-un is Kim Jong-il's third son and had already been identified as the most likely successor to the Communist dynasty started by his grandfather, Kim Il-sung, in 1948. The Workers' Party is holding its first meeting since 1980.