WASHINGTON - The death of North Korean leader Kim jong-il could dim hopes for fresh nuclear talks with the United States and its key Asian allies as an untested and largely unknown heir takes charge of one of the world's most feared atomic renegade states.The White House said on Sunday that President Barack Obama has been told of reports that Kim had died and was in close touch allies in South Korea and Japan, which along with Washington have been engaged in six-nation talks on North Korea's nuclear program. "We remain committed to stability on the Korean peninsula, and to the freedom and security of our allies," White House press secretary Jay Carney said in a written statement.But news of Kim's death comes at a tricky time for the Obama administration as it weighs whether to re-engage with Pyongyang on the nuclear issue and whether to provide food aid for millions of North Koreans hard hit by shortages.More crucially -- both for Washington and its close ally Seoul -- is the question of whether Kim's hermetic state can survive his death and complete a power transition that most analysts expect to favor his presumptive heir, leader-in-waiting Kim Jong-un.."Up until tonight, if anybody had asked you what would be the most likely scenario under which the North Korean regime could collapse, the answer would be the sudden death of Kim Jong-il," said Victor Cha, a Korea expert at the Center for Strategic and International Studies in Washington and a member of the White House National Security Council under former President George W. Bush."I think right now we're in that scenario, and we don't know how it is going to turn out. But I think we're definitely in it now," Cha said.Kim's reported death came as the US envoy for North Korean nuclear issues, Glyn Davies, returned to Washington for consultations after talks in Seoul, Tokyo and Beijing over the nuclear issue.US officials have said no decision on restarting the talks is imminent, but have also recently relaunched talks with North Korean diplomats on resuming food aid -- a step widely seen as a positive signal.The United States and its chief Asian allies have resisted calls to restart the so-called "six-party" talks involving the two Koreas, the United States, China, Japan and Russia which broke down in 2008, and United Nations inspectors were expelled from North Korea in 2009.US officials remain leery of North Korea's intentions and doubts have grown amid reports that Kim Jong-il's health problems were opening a transition plan to elevate to the top office his son Kim Jong-un -- a man believed to be in his late 20s, and about whom little is known.Some analysts said Kim's death -- and the transition to a young and untested leader -- could darken the outlook for the nuclear talks."Everyone's immediate refrain is 'Oh, great, a tyrant is gone,'" said Jim Walsh, a North Korea expert at the Massachussets Institute of Technology's security studies program."But actually this is bad news, because it means we are entering a more dangerous phase in North Korean, South Korean and US relations," Walsh said."Naturally, North Korea is going to be on the offensive. This young leader is going to have to prove his worth."The United States, backed by Japan and South Korea, has demanded that North Korea signal its sincerity on nuclear negotiations by halting provocative actions such as the sinking of a South Korean warship and the shelling of a South Korean island last year.Some North Korea watchers have attributed the two attacks to efforts by the younger Kim to demonstrate his leadership style, leading to fears that new provocations could strain the already tense relationship between North and South Korea."Kim Jong-un .... may feel it necessary in the future to precipitate a crisis to prove his mettle to other senior leaders or to generate a 'rally-around-the-flag' effect," said Bruce Klingner, an Asia policy analyst at the Heritage Foundation in Washington.Klingner said he believed fresh North Korean military action was unlikely in the near term."It is likely that such negotiations would be postponed as North Korea goes through a mourning period, formalized succession process and possible retrenchment of its foreign policies," he said in a written statement.Some North Korea experts said the leadership in Pyongyang was likely to focus internally over the medium term as it seeks to firm up control both during and after the succession."This competition can lead to internal conflicts," said security analysis group STRATFOR in a commentary, adding that once these conflicts are resolved it is possible Pyongyang may take a new attitude toward the nuclear talks."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," STRATFOR said.