Kim Jong -nam, the estranged half-brother of North Korean dictator Kim Jong-un, has been killed at an airport in Malaysia by North Korean agents who were reportedly wielding "poison needles."
Yonhap news said Kim Jong-nam, who is believed to be in his 40s, was killed on Monday morning in Kuala Lumpur.
Quoting government sources, other media reports claim Mr Kim died after being jabbed by a poisoned needle by two women in the city's airport.
The women are believed to be North Korean agents but have so far been able to evade a police hunt.
Police in Malaysia told Reuters that an unidentified North Korean man had died en route to hospital from Kuala Lumpur airport on Monday.
Mohmad Salleh, the Malaysian CID director, told the Telegraph: "Kim Jong Nam was feeling unwell on Monday morning while he was waiting for a flight to Macau at KLIA.
"He was taken to KLIA clinic for further treatment, but because of the condition he was in, he was rushed to Putrajaya hospital, but passed away soon after arriving.
"Police have classified the death of Kim Jong Nam as sudden death and are waiting for the full postmortem report to decide further action."
An employee in the emergency ward of Putrajaya hospital told Reuters that a deceased Korean who was born in 1970 and surnamed Kim had been taken there.
Who was Kim Jong-nam?
Kim Jong-nam was once considered the heir apparent to Kim Jong-il, but fell out of favour in 2001 after being arrested at Tokyo's Narita Airport after trying to enter Japan on a forged Dominican Republic passport.
He told police that he had wanted to visit Disneyland with his family.
Exiled by his father, he lived in Macau until Kim Jong-il died in late 2011. He subsequently went into hiding, apparently out of fear that his half-brother saw him as a threat to the legitimacy of his own regime.
The South Korean government is yet to respond to Yonhap News' report.
According to the South Korean newspaper Chosun Ilbo, Kim Jong-nam had previously worked for North Korea's foreign ministry.
He is said to have worked on resolving disputes with Japan, and was educated at a Japanese school.
Kim Jong-nam was reportedly handed the job by Kim Jong-un himself, in what was widely viewed as an attempt by the North Korean leader to keep his enemies close.
"I expect Kim Jong-un summoned Kim Jong-nam back to Pyongyang and gave him a job as he is still relatively weak and feared that other factions might support Kim Jong-nam," Toshimitsu Shigemura, a professor at Tokyo's Waseda University told the Telegraph in 2015.
"It is also possible that China is looking for an alternative North Korean leader and could have thrown their support behind another member of the Kim family."
What is South Korea's reaction?
The Korea Herald is reporting that the killing of Mr Kim in Malaysia has been reported to the South Korean National Security Council and to Hwang Kyo-ahn, the acting president, according to Foreign Ministry officials.
It is unclear whether the security status of South Korean troops has been upgraded.
Why was Kim Jong-nam killed?
If it is confirmed that the elder Mr Kim was assassinated at the behest of Kim Jong-un, it would not be the first attempt on his life.
One source told the Daily Mail in 2015 that North Korean spies attempted to kill Kim Jong-nam in Macau in 2011.
A bloody shootout with Mr Kim's bodyguards ensued, but he managed to escape with his life.
There has also been widespread speculation that Kim Jong-un felt threatened by his younger half-brother and had been planning to have him killed for some time.
However, Mr Kim said in an interview in 2010 that he had no ambitions of taking over from his younger half-brother.
"Personally I am against third-generation succession," he told Japan's Asahi TV.
"I hope my younger brother will do his best for the sake of North Koreans' prosperous lives."
He was known to be an advocate of reform in the North, which may have angered Kim Jong-un.
Hereditary succession is an integral part of the North Korean regime, according to Dr Adam Cathcart, at Leeds University.
"North Korea layered on principles of hereditary succession to what was already a well-established communist personality cult in the 1970s and 80s," he told the Telegraph.
"And as Kim Jong-il grew older it was clear the only way forward was to follow those principles over and above all the other alternatives which would have required change.
"Having had some experience abroad, Kim Jong-nam seems to have been repelled by the North Korean system, whereas Kim Jong-un has become fully enmeshed in it."
Kim Jong-nam admitted in another interview with Tokyo Shimbun that he had also grown apart from his father, Supreme Leader Kim Jong-il.
"After I went back to North Korea following my education in Switzerland, I grew further apart from my father because I insisted on reform and market-opening and was eventually viewed with suspicion," he told the newspaper.
How many executions has Kim Jong-un ordered?
North Korea does not release official figures on the number of citizens that it executes every year, although a report issued by South Korea's Institute for National Security in December 2016 claimed that Kim Jong-un had personally ordered the execution of 340 people since he came to power in December 2011.
The regime's willingness to execute anyone who shows anything short of complete loyalty to the regime is indicated by the scale of mass graves apparently discovered late last year using satellite imagery.
The majority of public executions are reportedly carried out with a single bullet to the condemned individual. There are a number of people, however, who have required more drastic demonstrations of the regime's displeasure.
Some have been executed by anti-aircraft weapons. On other occasions, flame-throwers were used.
And in at least one case, it seems, a mortar round was put to use on the execution grounds.
The most senior member of the present dictator was his own uncle, Jang Song-thaek, who was executed in December 2013 after being found guilty of a raft of crimes against the state, including "gnawing at the unity and cohesion of the party" and "dreaming different dreams".