South Korean and Chinese officials have publicly cast doubt on reports that Kim was gravely ill following a cardiovascular procedure, after his absence from a key state anniversary event on April 15 triggered speculation about his health.
But the media reports sparked questions about who is in place to take over if Kim, thought to be about 36, a third-generation hereditary leader, fell seriously ill or died. He became leader when his father Kim Jong Il died in 2011 from a heart attack.
Each change at the top in North Korea has raised the prospect of a leadership vacuum or collapse of the Kim dynasty, which has ruled the country since its founding in 1948.
So far, each of the three Kims to rule North Korea has defied expectations, holding on to power with an iron grip. But under Kim Jong Un, North Korea’s arsenal of nuclear weapons and ballistic missiles has grown substantially, raising concerns over who would control them.
The following are key figures in the North Korean leadership circle and what role they may play in any transition.
Kim’s younger sister has been the most visible presence around the leader in the past two years, serving formally as a vice director of the ruling Workers’ Party’s powerful Central Committee but unofficially as her brother’s chief of staff.
Kim Yo Jong was named an alternate member of the ruling Workers’ Party’s powerful Central Committee Politburo this month, continuing her climb through the leadership hierarchy.
The leader’s sister, believed to be 31, has a firm control of key party functions, setting herself to be the main source of power behind a collective leadership.
“Kim Yo Jong will be for the time being the main power base with control of the organisation and guidance department, the judiciary and public security,” said Cho Han-bum of the Korea Institute for National Unification, a government-funded think-tank in Seoul.
Choe Ryong Hae rose to be North Korea’s nominal head of state last year as president of the Presidium of the Supreme People’s Assembly.
This capped decades of service with the party for the ruling Kim family, following his role as the influential political head of the military under the young leader.
Choe and Pak Pong Ju, a fellow politburo member and former state premier who oversaw the North’s push to introduce more free-market functions to revive its economy, are likely to be the figureheads leading a collective leadership, analysts say.