By Jill Dougherty and Adam Levine
The sudden death of Kim Jong Il is the "biggest shock you could have thrown into Asia," an expert on North Korea told CNN late Sunday night.
Victor Cha, who worked in White House National Security Council, says one of the likelier scenarios under which the North Korean regime could crumble was the sudden death of Kim Jong Il - and now it has happened.
"No one has any idea of what comes next," Cha said. "We are in unknown territory."
That uncertainty should have people on edge, a U.S. official told CNN's Pam Benson.
"An insecure North Korea could well be an even more dangerous North Korea," the official said.
Kim's son and heir, Kim Jong Un, is simply "not ready" to rule, Cha said.
He is barely 30, and his father began grooming him for the job only three years ago after the latter suffered a stroke.
In contrast, the elder Kim was prepared for his own position over a period of 14 years.
Kim Jong Un holds the rank of general and is second-in-command of the military but did not come up through the ranks.
He was made a general in order to have him in the job so he would be prepared eventually to take over from his father, experts said.
It is likely that Kim Jong Un's uncle, Jang Song Thaek, will rule behind the scenes as Kim Jong Un trains on the job, according to an analysis distributed by Stratfor.
Cha said an important next step will be to watch what happens on the ground in North Korea. But that may prove hard since the state is so reclusive.
Another thing to watch for is whether U.S. troops in South Korea will go on a higher level of alert.
Finally, the role of China is crucial since it is the only country that has any close understanding of what the regime is doing.
Cha said it is likely President Barack Obama will reach out to China, but Beijing often is not willing to share its knowledge with the United States.
Ironically, things were looking calmer in recent months.
The United States was inching back to talk with North Korea, and Pyonyang itself was preparing to mark the 100th anniversary of the birth of the Kim Il Sung in April 2012.
The worst case scenario would be chaos in North Korea, Cha said, and the danger of loose nuclear weapons.
The North might also act out in a more belligerent fashion militarily amidst the uncertain transition.
There is also the possibility that Kim Jong Un uses a military action to prove his mettle, observes RAND's Bruce Bennett, an Asia analyst who has worked with the U.S. Department of Defense, as well as South Korean and Japanese militaries.
"North Korean leadership demands appearance of empowerment. Kim Jong Un is going to be tempted to do something to show how powerful he is," Bennett said in a phone interview Sunday night. "It could be testing a nuclear weapon or a missile test."
But Bennett said it is unlikely anything official will become apparent before the mourning period is over.
The funeral, which North Korea's media outlet said will be December 28, could provide a first look at the state of leadership, Bennett said.
Bennett said it took Kim Jong Il three years to consolidate his power.
"The funeral will be important to monitor to see if the people we expect to see in power are still there or will Kim Jong Un purge to show he is in position to do so," Bennett said.
Jong Il’s son has a lot to prove. He was tied to the disastrous effort to revalue the North Korean currency, Bennet said.
That effort led to protests, a shocking development in the closed country and food shortages as people took to bartering in absence of available currency.
As such, it is less likely that Kim Jong Un would set off in a different direction given his entire legitimacy is based on being the heir to his father and grandfather.
"Like the transition from Kim Il Sung to Kim Jong Il, it is likely that North Korea will focus internally over the next few years as the country's elite adjust to a new balance of power," the Stratfor analysis noted. "In any transition, there are those who will gain and those who are likely to be disenfranchised, and this competition can lead to internal conflicts."
Even so, Bennett said this is also a time for the United States to start to probing for any chance the new leader is going to step out from his father’s shadow and try different. While it is unlikely that Kim Jong Un will try anything new, "we ought to try to float things to see."
The analysts at Stratfor say bringing North Korea back to six-party talks is not out of the question.
"Kim's death does not necessarily put an end to recently revived discussions with the United States and others over North Korea's nuclear program. Pyongyang has increasingly felt pressured by its growing dependence on China, and these nuclear talks provide the potential to break away from that dependence in the long term," the Stratfor analysis stated.
Bennett said an Arab Spring-like uprising is highly unlikely in a country like North Korea. However, if Kim Jong Un mismanages the country "the kind of rebellion I could see in North Korea would be among the elites, especially the senior elites," he said.
"At some point in time, the senior leadership would take action. But they would be putting their lives on the line to do that."