Media reports say Kim Jong-nam was reportedly poisoned at Kuala Lumpur airport.

The estranged half-brother of North Korean leader Kim Jong-un has been killed in Malaysia, South Korean media reported, with one TV station saying he was attacked at the country's main airport with poisoned needles, according to Al Jazeera.

In a statement, Malaysian police said the 46-year-old dead man was travelling on a passport under the name Kim Chol.

Kim Jong-nam has been known to travel using a fake name, Al Jazeera said. 

TV Chosun, a cable television network, said separately that Kim Jong-nam was poisoned at Kuala Lumpur airport by two women believed to be North Korean operatives, who were at large, citing multiple South Korean government sources.

Kim Jong-nam and Kim Jong-un are both sons of former leader Kim Jong-il, who died in late 2011, but they had different mothers.

Kim Jong-nam was known to spend a significant amount of his time outside North Korea, travelling to Hong Kong, Macau and mainland China.

In 2001, Kim Jong-nam was caught at an airport in Japan travelling on a fake passport, saying he had wanted to visit Tokyo Disneyland.

He said several times over the years that he had no interest in leading his country.

Los Angeles Times reports that once considered the successor to his father, Kim Jong-il, Kim Jong Nam had been living incognito in exile in Macau, reportedly under the protection of the Chinese government. Even though he disavowed any aspirations to leadership, North Korea watchers invariably raised his name as a potential replacement in the case of a coup d’etat against Kim Jong Un.

Kim Jong-un’s aunt told The Washington Post last year that the current leader was chosen as successor in the early 1990s, when he was only 8 years old.  In 2010, with Kim Jong-il’s health steadily worsening, Kim Jong-un was officially declared heir apparent.

Malaysia is one of a dwindling number of countries that has close relations with North Korea, which is under tightening global sanctions over its nuclear tests and ballistic missile launches, the latest of which took place on Sunday.

Malaysians and North Koreans can visit each other's country without visas.