North Korean leader Kim Jong Un reportedly fears being assassinated while traveling to Singapore to meet with President Donald Trump.

Kim has long feared assassination, even within his own country.

While in transit and in Singapore, he'll be almost defenseless against sophisticated attempts on his life.

Kim's constant fear of assassination may seem paranoid, but his own half brother was killed in an airport in Malaysia, right next to Singapore.

Singapore has taken remarkable measures to guarantee the security during the summit, including blocking off parts of the city and restricting airspace.

North Korean leader Kim Jong Un reportedly fears being assassinated on his way to Singapore to meet with President Donald Trump, a trip that will take him further outside of his country than he's been since taking power in 2011.

Kim is "extremely worried about security at the summit and is fearful of assassination attempts," Bloomberg quoted two sources familiar with the talks as saying.

Kim has long feared assassination, even within his own country. But as the leader of a country that frequently threatens the US with nuclear war, getting on a plane and flying across international airspace to a neutral country provides him even less security.

Even along the DMZ with South Korea, Kim traveled with an impressive security detail.

But North Korea has virtually no air force, and will place its leader on a civilian airliner in a region stacked with surface-to-air threats and a large US military aviation presence. As the downing of flight MH-17 proved, airline crashes can be denied.

North Korea maintains that the US has a "hostile policy" towards it and think it would attempt regime change given the chance.

Comments from Trump's National Security Adviser John Bolton comparing North Korea to Libya, where its leader was killed in a US-backed intervention, may have stoked these fears.

But while Kim's constant fear of assassination may seem paranoid, it's not unfounded. China is rumored to have looked into an assassination plot involving Kim's uncle, whom Kim ended up killing.

Kim's half brother, Kim Jong Nam, was also assassinated in neighboring Malaysia with a nerve agent that authorities suspect Kim ordered.

Furthermore, Kim is more vulnerable to assassination than his counterpart, Trump. Kim is the patriarch of a dynasty, while Trump is just the president.

If Kim dies without a clear successor, his country could descend into chaos.

If a US president dies, there's a long-established chain of succession, and if North Korea were involved in the death, there would be hell to pay.

Singapore has taken remarkable measures to guarantee the security of the summit, including blocking off parts of the city and restricting airspace during the summit.

Insiders say Kim is seeking security guarantees from the US in exchange for acts of denuclearization, but Kim's constant fear of assassination points to the inherent instability of his dictatorial rule.