WASHINGTON – With the death of North Korean strongman Kim Jong Il, experts said Monday, the nuclear-armed nation is likely to retreat into greater seclusion from the world while the political transition sorts itself out.

“The leadership will be in a hunker-down mode for at least the next couple of months or possibly longer,” said Peter M. Beck, a longtime North Korea watcher and fellow at the Council on Foreign Relations.

Additional Photos

Kim Jong Un, right, and his now-deceased father, Kim Jong Il, attend a military parade last year. North Koreans are unfamiliar with Kim Jong Un, whose name was mentioned in public only 15 months ago and whose father never explicitly endorsed him as his successor. The Associated Press

Related Headlines

• N. Korea’s young new leader could face a power struggle

Pyongyang’s propaganda arm wasted no time in labeling Kim Jong Il’s third son, Kim Jong Un, a Swiss-educated man thought to be 27 years old, as a “great successor” and a “distinguished leader of the military and people.” But North Koreans are as unfamiliar with Kim Jong Un as the rest of the world is.

His name was mentioned in public for the first time only 15 months ago, when he was promoted to a four-star army general despite a thin leadership record. His father never explicitly and publicly endorsed him as successor.

“We know very little about him. He was brought into the public eye in September of last year, and this is not enough to give him legitimacy,” said Ruediger Frank, a North Korea expert at the University of Vienna.

FOR U.S., OPPORTUNITY OR DANGER?

In a sign that North Korea was sealing itself off for a period, the nation said it wouldn’t accept foreign delegations for Kim Jong Il’s funeral Dec. 28 or a national memorial service the next day, when guns will boom, sirens will wail and three minutes of silence will descend on the world’s last Stalinist state.

Television images showed North Koreans weeping and falling to the ground to lament the passing of the 69-year-old strongman known as the “dear leader.”

President Obama and other world leaders turned their eyes to North Korea, which conducted nuclear tests in 2006 and 2009, aware that the transition could bring opportunity for new engagement — or lead to deadly provocations on the Korean peninsula.

The White House said Obama had spoken with South Korean President Lee Myung-bak to reaffirm Washington’s “strong commitment to the stability of the Korean peninsula.”

Secretary of State Hillary Clinton met Monday with Japanese Foreign Minister Koichiro Gemba, and senior administration officials also spoke with their South Korean counterparts and with top officials in Russia and China, the other members of six-party talks on North Korea’s nuclear program, the White House said.

Asked whether the Obama administration considered Kim’s death an opening, White House spokesman Jay Carney said it was “much too early to make any kind of judgment like that.” Carney said North Korea was in a period of “national mourning” and that it was premature to make any assessments about the new leadership.

“We will judge the North Korean government by its actions,” he said.

‘A NEW ERA OF UNCERTAINTY’

Unlike his father, who had 15 years to prepare to take over North Korea, Kim Jong Un had less than two years. Experts say that after an initial period of calm, a rocky transition may unfold.

“North Korea is entering a new era of uncertainty, with profound and unsettling implications for all the countries in the region,” Charles K. Armstrong, the director of Korean research at Columbia University, wrote in a statement for the Asia Society.

Just where Kim Jong Un might take North Korea — toward reform or more hard-line policies — is unclear.

Seeds of reform are already present in a country that’s no longer the utterly closed society it remained for decades after World War II.

For one thing, cellular telephones are now prevalent. As of Oct. 1, the nation had 809,000 registered cellphone users, according to Orascom Telecom, the Egyptian company brought in as a 75 percent stakeholder in koryolink, a national cellular service provider.

Within weeks, that figure is expected to top 1 million — which would be about 4 percent of North Korea’s 24.5 million population — and although they can make and receive only domestic calls, experts note that it’s a far greater number than can be monitored individually.

“It’s not Twitter. It’s not Facebook. It’s not the Internet. It’s not the means to reach a lot of people at the same time,” said Frank, the scholar in Vienna. “But it helps with the exchange of information. It’s clearly a factor.”

“North Koreans are more easily able to communicate with each other,” Beck echoed, noting the presence also of illegal radios tuned to South Korean broadcasts.

NEW LEADER MORE OPEN TO CHANGE

Kim Jong Un, who’s the grandson of deceased North Korean founder Kim Il Sung, is familiar with new technologies, according to those who have known him, including a Japanese sushi chef who worked as a personal cook for the Kim family for more than a decade.

The chef, who goes by the pen name Kenji Fujimoto and returned to Japan in 2001, wrote in one tell-all book that the heir apparent drove a Mercedes-Benz 600 sedan, smoked French cigarettes, listened to South Korean pop music, played basketball and enjoyed computer games.

The Nautilus Institute — a research center with offices in San Francisco, Seoul and Melbourne, Australia — issued a statement Monday saying Kim Jong Un is “likely to be more open to rapid, structural change in the economy. Whether he can bring along his senior advisers in embracing the notion of structural change is another matter.”

The possibility looms, however, that Kim Jong Un won’t easily consolidate his grip on the nation, prompting him to radical action to burnish his credentials.

“We may see provocations of the kind designed to enhance his leadership and his image,” said Paul B. Stares, a conflict prevention expert at the Council on Foreign Relations.

Only two months after Kim Jong Un’s name was first mentioned in public, with his installation as vice chair of the Central Military Commission of the Workers’ Party of Korea, North Korea embarked on a deadly artillery attack on a front-line South Korean island.

GUIDANCE FROM AN UNCLE

News reports in South Korea routinely say that Kim Jong Un played a role in the artillery attack on Yeonpyeong Island on Nov. 23, 2010, which killed two marines and two civilians and led to fears of war.

The attack came after the sinking of a South Korean warship that March, killing 46 South Korean sailors, which plunged inter-Korean relations to their lowest point in years.

Among the inner circle of the Kim family, experts are watching Kim Jong Un’s uncle, Jang Song Thaek, who’s likely to rule behind the scenes as Kim Jong Un trains on the job. Jang is married to the late dear leader’s sister, who’s also powerful.

“He might act as a caretaker of his nephew. Or he might use the opportunity to take power for himself,” Frank said.

Jang is one of four top leaders with interlocking complementary titles. The others are army Vice Marshal Kim Yong Chun, state security chief Gen. U Tong Chuk and O Kuk Ryol, vice chair of the National Defense Council.

Related Stories