Kim Jong Nam, the half-brother of North Korean leader Kim Jong Un, has been assassinated at an airport in Kuala Lumpur.

According to a Malaysian official, 46-year old Jong Nam told medical workers before he died that he had been attacked with a chemical spray.

The senior government official, who spoke on condition of anonymity on Tuesday said, Nam was targeted Monday in the shopping concourse at the airport and had not gone through immigration yet for his flight to Macau.

The official said, he was taken to the airport clinic and then died on the way to the hospital.

Kim Jong Nam was estranged from his younger brother, the North Korean leader. He had been tipped by outsiders to succeed their dictator father, but reportedly fell out of favour when he was caught trying to enter Japan on a false passport in 2001, saying he wanted to visit Tokyo Disneyland.

Sources in South Korea said Kim Jong Nam was killed at the airport by two women believed to be North Korean agents. They fled in a taxi and were being sought by Malaysian police, the reports said.