TOKYO - Kim Jong Il, North Korea's supreme leader, took new steps Tuesday to ensure that his family remains in charge after his death, but the biggest leadership shuffling in a generation has so far produced more political intrigue than signs of real change in North Korea, one of the world's most isolated nations.

Kim elevated his sister and a close friend to a high military ranking and had his youngest son and heir apparent, Kim Jong Un, made a member of the Central Committee of the ruling Workers Party.

The promotions came a day after the younger Kim was also made a four-star general and seemed aimed at ensuring a dynastic succession that would give Kim Jong Un, thought to be in his late 20s, time to solidify his power.

The elevation of the completely unknown Kim, and hints that other members of the extended Kim clan will exercise power behind the scenes in a kind of Communist regency, add to the uncertainty about North Korea. The country appears to have mostly abandoned its incipient economic reforms and has declined to enter new international talks about its nuclear weapons program, leaving its neighbors and the United States alarmed about its intentions.

Few analysts claim to fully understand the inner workings of the North Korean military or the Kim dynasty. But many who watch the country closely say they see few signs that succession will produce a stable, credible leadership that is, at least initially, confident enough to engage with the outside world or to steer resources to economic development rather than the military.

"We worry about Pakistan, but this is potentially every bit as destabilizing as Pakistan," said William Keylor, a professor of international relations at Boston University. "Succession in North Korea would just be an oddity if were not for the fact that we are dealing with a country with nuclear weapons and delivery systems. That is what makes this serious."

The previous succession

Fear of instability also followed the death of Kim Il Sung, North Korea's founding leader, and the rise of his son, Kim Jong Il, in 1994. The country did not collapse then, although its economic performance deteriorated sharply and millions of North Koreans are thought to have starved to death during Kim Jong Il's erratic tenure.

This time, the country appears less well prepared for a transition. Kim Jong Il had 14 years between his political introduction in 1980 and his father's death, time he used to build support internally. There are few signs that a succession process had even begun when Kim Jong Il, now 68, apparently suffered a stroke two years ago.

Some analysts predict that new leaders may feel compelled to prove their nationalist credentials by engaging in provocative actions that could worsen tensions with South Korea and Japan and their main ally, the United States. In March, South Korea accused the North of sinking one of its warships, the Cheonan, which some analysts say appears to have been a display of force meant to persuade the military to respect the younger Kim.

"The question now is whether they will do dangerous things like the Cheonan or something else to hold the regime together," said Victor Cha, director of Asian studies at Georgetown University. "They were already unstable as it was, and this succession issue makes them even more unpredictable."

China's role in the North

In the most destabilizing situation, an internal power struggle could also lead to the collapse of the government. But many observers discount that possibility, largely because of the support of another neighbor, China. Beijing has made it clear that it is determined to avoid a political eruption on its borders.

The reasons behind the elevation of Kim Jong Il's sister, Kim Kyong Hui, and Choe Ryong Hae, a lifelong friend of the Korean leader, were uncertain. Experts suggested that they, along with the sister's husband, Jang Song Taek, might end up forming a new ruling group with Kim Jong Un that could keep the military in check and continue the Kim dynasty, at least until the son can fully replace his father.

As the succession scenario unfolded, the South Korean Defense Ministry announced that there would be talks between the two nations' militaries on Thursday at Panmunjom, the first such talks in two years.