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.

朝鲜领导人金正日最小的儿子被任命两项重要的党内职务，此举被广泛认定为逐渐转移权力举措的一部分。

The younger Mr Kim is thought to be in his late 20s and has no military experience

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 four-star 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.

It's a remarkable¹ rise, even by the standards of one of the world's most totalitarian（极权主义的） states, says the BBC's John Sudworth in Seoul.

There can now be little doubt that he has been chosen to eventually take over from his ailing²（生病的，体衰的） father, our correspondent says.

Military priority

Little is known of Kim Jong-un other than that he was educated in Switzerland and is about 27 years of age.

The Workers' Party has been holding its first meeting since 1980.

The conference also made the leader's sister a member of the political bureau and her husband an alternate member, the state-run KCNA news agency reported.

The pair had been considered key backers of the young son.

BBC diplomatic correspondent Jonathan Marcus says uncertainty³ surrounds the transitional arrangements.

It is unclear whether the older Mr Kim will gradually relinquish⁴（放弃） power or whether a third figure - such as powerful National Defence Commission Chairman Jang Song-thaek - will act as the younger Kim's mentor⁵.

Alternately, our correspondent adds, a struggle for power could develop if Kim Jong-il's grip weakens.

The priority of military positions in North Korea's secretive power apparatus⁶ stems from the policy known as "songun" or military first.

The military, backed up by a standing⁷ army of 1.2 million troops, is said to run the country's political process through the National Defence Commission, chaired by Kim Jong-il.

The 68-year-old leader has been described as frail⁸ and is said to have had a stroke two years ago.

Kim Il-sung is known as the "eternal president", while Kim Jong-il has styled himself the "dear leader".

Kim Jong-il became leader when his father died in 1994.

Under his rule, the country's isolation⁹ from the outside world has become entrenched¹⁰（根深蒂固的，确立的） .

Mr Kim has built up a personality cult¹¹（个人崇拜） around his family, while North Korea's economy has all but ceased to function and its people suffer from frequent food shortages.