Police have obtained an International Criminal Police Organisation (Interpol) red notice for the four North Korean suspects believed to be behind the murder of Kim Jong-nam.

"I would like to inform you that we have obtained Interpol red notice for the four North Korean nationals who were at the airport on the day of the incident and who have since left and we believe to be in Pyongyang now," inspector-general of police Khalid Abu Bakar told reporters in Putrajaya today.