Police have been able to confirm the identity of Kim Jong Nam, who was killed last month at Kuala Lumpur's airport, using a DNA sample from one of his children, a Malaysian official said.

North Korea said it was banning Malaysians from leaving the country as its diplomatic battle escalated dramatically over the poisoning death of Kim Jong Nam, the North Korean leader's estranged half brother.

North Korea's ambassador to Malaysia faces a deadline to leave the country after authorities moved to expel him and accused Pyongyang of trying to manipulate the investigation into the poisoning of Kim Jong Nam.