Kim Jong-nam arrives at Beijing International Airport in 2007. Credit:Getty Images He was known to have spent most of his time outside North Korea and had spoken out publicly against his family's dynastic control of the isolated state. Malaysian police official Fadzil Ahmat told Malaysian state news agency Bernama that the deceased had been approached from behind. "A woman came from behind and covered his face with a cloth laced with a liquid," he said. "The deceased ... felt like someone grabbed or held his face from behind," Mr Fadzil said. "He felt dizzy, so he asked for help at the... counter of KLIA (airport)."

Police officers wait at the forensic department entrance at a hospital in Putrajaya, Malaysia, where Kim Jong-nam's body was taken. Credit:AAP Mr Fadzil said Kim Jong-nam had been planning to travel from Kuala Lumpur to Macau, where he had been living under Chinese protection and was quoted in 2012 as saying North Korea needed "Chinese-style economic reform". "I have conveyed the matter to the North Korean embassy," Mr Fadzil said, adding that an autopsy was planned to seek the cause of death. North Korean leader Kim Jong-un pictured in Pyongyang in 2016. Credit:AP Police were checking surveillance tapes on Wednesday to try to identify the attackers.

Police are also investigating Mr Kim's movements in Malaysia after he arrived in the country on February 6 on a flight from Macau. Kim Jong-nam's father was former North Korean leader Kim Jong-il. Credit:AP Police said Malaysia has received a request to send the body to North Korea but it would not be released until completion of a post-mortem, which was being undertaken on Wednesday. Malaysia is one of a dwindling number of countries that has close relations with North Korea, which is under global sanctions over its nuclear and ballistic missile launches. Malaysians and North Koreans can visit each other's countries without visas. The North Korean embassy in Kuala Lumpur has made no comment.

South Korea's acting president and prime minister Hwang Kyo-ahn described the apparent assassination as a "brutal and inhumane" example of the nature of Kim Jong-un's regime. "Based on the understanding that this case is of great importance, our government is keeping close tabs on North Korea's movements," Mr Hwang said during a special session of his country's national security council on Wednesday. He reiterated a call for strengthened sanctions and pressure to force North Korea to abandon its nuclear ambitions. In October 2012, South Korean prosecutors said a North Korean man detained as a spy had admitted involvement in a plot to stage a hit-run accident targeting Kim Jong-nam in China in 2010. South Korean media outlets reported Kim's death in Kuala Lumpur was the result of a planned attack by North Korean spies, with some South Korean outlets originally claiming it had been carried out using "poison needles".

One of the outlets, Chosun, citing multiple local sources, claimed two women believed to be North Korean intelligence agents fled the airport in a taxi. "I think the two were female spies dispatched by North Korea," said an intelligence official, quoted by the Korea Joongang Daily. A South Korean government source confirmed the death to Reuters. There was no immediate comment from North Korea. In a statement, Malaysian police said the dead man held a passport under the name Kim Chol, born in Pyongyang on June 10, 1970. Kim Jong-nam is believed to have been born on May 10, 1971.

But Ken Gause, an American expert on North Korea, said Kim had previously travelled under the name Kim Chol. Mark Tokola, vice-president of the Korea Economic Institute in Washington and a former diplomat in South Korea, said it would be surprising if Kim Jong-nam was not killed on the orders of his half-brother, given that North Korean agents have reportedly tried to assassinate him in the past. "It seems probable that the motivation for the murder was a continuing sense of paranoia on the part of Kim Jong-un," he said. The North Korean leader has carried out a series of purges since assuming power five years ago which the South Korean government has described as a "reign of terror". South Korea's national news agency Yonhap quoted a source saying agents of the North's spy agency, the Reconnaissance General Bureau, carried out the assassination by taking advantage of a security loophole between Kim's bodyguards and Malaysian police at the airport.

South Korea's foreign ministry said it could not confirm the reports on Chosun regarding the two female spies, and the country's intelligence agency could not immediately be reached for comment. A US government source told Reuters it believed North Korea agents were responsible but did not provide evidence for that conclusion, and also said it was possible that Kim had been poisoned. Kim Jong-nam was for many years considered the heir apparent to his father but is believed to have fallen out of favour in 2001 after he was caught trying to enter Japan on a false passport, saying he had wanted to visit Tokyo Disneyland. The Joongang Daily quoted an intelligence official as saying Kim had been in a relationship with a woman in Malaysia and travelled there often. In 2013 Kim Jong-un's uncle Jang Song-thaek, once considered the country's second most powerful man, was executed and key figures linked to him purged. Kim Jong-nam had reportedly been close to his uncle.

In 2008 Kim Jong-nam reportedly suffered a stroke after which he travelled frequently to countries in South-east Asia and the Chinese territory of Macau. In 2012 he was reportedly having financial troubles and was evicted from a Macau hotel over a $US15,000 debt. His mother is the late Kim Jong-il's second wife, Song Hye-rim, a South Korean-born actress and one of at least three women with whom the former leader had children. The death became public late on Tuesday as the United Nations Security Council condemned Kim Jong-un for his country's firing of a ballistic missile on Sunday, the first direct challenge to the international community since US President Donald Trump took office on January 20. North Korea's media rejected the criticism on Tuesday, saying launching the missile with a range of 2000 kilometres was a "self-defence measure".

Loading Mr Trump, who was in the US with Japanese Prime Minister Shinzo Abe at the time of the launch, said, "I just want everybody to understand and fully know that the United States of America stands behind Japan, its great ally, 100 per cent." with agencies