Sept. 28 (Bloomberg) -- Kim Jong Il’s youngest son was named a general, signaling the start of a possible power transfer in North Korea to a man said to be in his late 20s who has never previously been mentioned in public.

Kim Jong Un was one of six people given the rank ahead of North Korea’s biggest leadership gathering in 30 years, which starts today, the official Korean Central News Agency reported. The orders were issued by Kim Jong Il, who serves as Supreme Commander of the Korea People’s Army, it said, without mentioning the family link.

The timing of the party congress is significant because it’s taking place as Kim’s failing health forces him to pass on leadership responsibilities, U.S. and South Korean officials have said. The last such gathering in 1980 secured Kim’s position as heir to his father, North Korean founder Kim Il-Sung.

“This is a prelude to officially designating Kim Jong Un as the next leader at the party congress by appointing him to key party posts,” said Kim Yong Hyun, professor of North Korean studies at Seoul-based Dongguk University. “It seems a little hasty for Kim Jong Il to be revealing his son at such a young age, but he must have felt time is running out with his health deteriorating.”

Kim Jong Il’s sister, Kim Kyong Hui, was also promoted to the rank of general, KCNA said. Her husband, Jang Song Thae, was named vice chairman of the National Defense Commission in June, making him North Korea’s second-most powerful official.

‘Watching Developments’

“The United States is watching developments in North Korea carefully,” Kurt Campbell, assistant secretary of state for East Asia, said yesterday in a conference call from New York after the KCNA announcement. “But frankly, it’s too early to tell, in terms of next steps, what’s going on inside the country’s leadership.”

Kim Jong Il, 68, made his second trip this year to China in late August in what analysts said was an effort to win the endorsement of his closest ally for a power transfer to his son. Chinese Premier Wen Jiabao lauded the party congress as “a political event of great significance,” KCNA said Sept. 2.

Little is known about Kim Jong Un. He attended the International School of Berne in Switzerland, according to media including the Seoul-based Dong-A Ilbo newspaper. KCNA has never mentioned the son by name and China didn’t say whether he accompanied his father during the most recent visit.

North Korea may also use the congress to announce new policies to reinvigorate the country’s faltering economy, which was dealt a further blow this year after floods wiped out crops and damaged houses.