TOKYO - North Korea's ailing leader has chosen his youngest son - who is just 26, attended a Swiss boarding school, and reportedly admires basketball great Michael Jordan - as heir to the dynasty that rules the secretive state, South Korea's intelligence service told lawmakers in Seoul.

Kim Jong Un is the third son of Kim Jong Il, the "Dear Leader" who suffered a stroke last summer and who has since appeared thin and frail. He is the grandson of the late Kim Il Sung, the "Great Leader" and founding dictator of North Korea.

If Kim Jong Un does become the new leader - and there are analysts who doubt the decision is final - this second consecutive father-to-son handoff would be unique among nations that call themselves communist. There was no indication, however, that Kim Jong Il would be handing over power any time soon.

South Korea's National Intelligence Service declined to confirm the reports.

Kim Jong Un attended the International School of Berne, which is 15 minutes outside the Swiss capital and a few hundred yards from the North Korean Embassy.

While Kim was at the English-language school, which has 280 students from 40 countries, he befriended the children of American diplomats and learned French and German, according to the Swiss weekly L'Hebdo.

Kim attended the school under the pseudonym Pak Chol, the weekly said, and school officials and his classmates "thought they were dealing with the son of the driver of the embassy."

Friends and staff at the school recall a shy boy who enjoyed skiing, loved the NBA and Michael Jordan, and spoke highly of action-movie actor Jean-Claude Van Damme.

He reportedly left the school at 15 to return to North Korea, and little about his life there is known by the outside world.

His name surfaced about four months ago as his father's likely successor, but it wasn't until after last week's underground nuclear test that Kim Jong Il informed top officials in Pyongyang and diplomats in foreign missions that Kim Jong Un would be his successor, intelligence officials told members of the National Assembly in Seoul.

One of those lawmakers, Hong Jung Wook, a member of the ruling Grand National Party, said that intelligence officials believe the recent spike in military and political tension is closely related to the transitional process underway in Pyongyang.

"Kim Jong Un is very young" and "seems to need support from the military and seems to be conforming to military preferences in his policy direction," Hong said.

Schoolchildren in Pyongyang have begun singing the praises of Kim Jong Un, according to a report from Rescue the North Korean People, a relief group in Osaka, Japan, that has informants inside North Korea.

Kim Jong Un is the second son of Kim Jong Il's third wife, Ko Yong Hi, who died five years ago of breast cancer at age 51.

Kim Jong Il, 67, has two other sons. The eldest, Jong Nam, 38, lost favor in 2001, when he was caught trying to enter Japan on a phony passport. He told Japanese officials he wanted to visit Disneyland in Tokyo.

The middle son, Jong Chol, was regarded by his father as unfit for leadership, according to Kenji Fujimoto, a former Japanese sushi chef for the North Korean leader.