North Korean dictator Kim Jong Un has now missed two major events, fuelling speculation about his health. 

Questions have been mounting about the leader’s condition, but increased dramatically on Saturday when American tabloid TMZ published and article claiming he had died – citing unsubstantiated reports from Chinese and Japanese sources. 

But Kim has been out of the public eye for extended periods of time before, and the secretive nature of the state means it’s difficult for reliable information about his health – let alone his ability to continue to lead – to come to light. 

Here’s what we know so far about Kim’s health, where he might be, and who could follow him into power if he’s incapacitated: 

What condition is Kim in?

There have been plenty of rumours about the dictator’s health in recent weeks, and North Korean authorities have not yet revealed any information about Kim’s health.

Questions about Kim’s condition flared after he missed an April 15 commemoration of the 108th birthday of his grandfather, North Korea founder Kim Il Sung.

The annual commemoration is North Korea’s most important event, and Kim, 36, had not missed it since inheriting power from his father in late 2011.

North Korea’s state media on Wednesday said Kim sent a message thanking Syria’s president for conveying greetings on his grandfather’s birthday, but did not report any other activities.

It was later reported by Seoul-based speciality website Daily NK that Kim was recovering at a coastal villa after undergoing a cardiovascular procedure on April 12, citing unidentified sources.

On Saturday, Kim missed another national holiday, North Korea’s Military Foundation Day, adding to growing questions about his health. 

On Monday night American news outlets published and tweeted reports that the leader was in a serious condition – with CNN reporting that Kim was in “grave danger” and NBC News later claiming he was “brain dead” (though the tweet containing the claim was later deleted “out of an abundance of caution”).

Without elaborating on whether or not Kim had undergone surgical procedure, two South Korean government sources cast doubt on the reports he is gravely ill and the presidential Blue House said there are no unusual signs coming from the North.

An official at the Chinese Communist Party’s International Liaison Department, which deals with North Korea, told Reuters the source did not believe Kim was critically ill. China is North Korea’s only major ally.

A US source familiar with internal US government reporting on North Korea backed up the South Korean account and questioned the CNN report that Kim is seriously ill, even though he has been out of the public eye for an extended period.

Where is he?

Satellite imagery has found a train likely belonging to Kim Jong Un as speculation continues over his health, according to a website specialising in studies of the country.

The satellite photos provided by website 38 North and Airbus show the train has been parked at Kim’s compound in Wonsan on North Korea’s east coast since at least April 21.

The photos do not provide any clarity on Kim’s health, but they do appear to confirm South Korean government intelligence that he is staying outside of the capital, Pyongyang.

Who could succeed Kim if he were left unable to lead?

Kim is the third generation of his family to rule North Korea, and a strong personality cult has been built around him, as well of the legacy of his father and grandfather.

The family’s mythical “Paektu” bloodline, named after the highest peak on the Korean Peninsula, is said to give only direct family members the right to rule the nation.

Following that line, Kim’s younger sister – senior ruling party official Kim Yo Jong – would be the most likely candidate to step in if her brother is gravely ill, incapacitated or dies.

But some experts say a collective leadership, which could end the family’s dynastic rule, could also be possible.

A collective leadership would likely be headed by Choe Ryong Hae, North Korea’s ceremonial head of state who officially ranks a second-in-command in the country’s current power hierarchy.

But Choe is still not a Kim family member, and that could raise questions about his legitimacy and put North Korea into deeper political chaos, according to other observers.

Other Kim family members who might take over include Kim Pyong Il, the 65-year-old half-brother of Kim Jong Il, who reportedly returned home in November after decades in Europe as a diplomat.