South Korea has confirmed the killing of the brother of North Korea’s leader Kim Jong-un, saying it could be a sign of the brutality of Pyongyang.

Kim Jong-nam was killed in an apparent poison attack in the Malaysian capital, Kuala Lumpur, on Monday.

No motive has been confirmed and the attackers have not been identified.

South Korea’s acting president Hwang Kyo-ahn said if North Korea was found to be responsible, it would show its “brutality and inhumane nature”.

If confirmed, it would be the most high-profile death at the hands of the North Korean leadership since Kim Jong-un’s uncle, Chang Song-thaek, was executed in 2013.

Mr Kim appears to have been attacked with a chemical while preparing to board a flight home to Macau from in Kuala Lumpur’s airport on Monday.

His death was made public only on Tuesday. On Wednesday morning, his body was released from hospital. A post-mortem examination was expected to be conducted.

A Malaysian police official, Fadzil Ahmat, told Reuters that so far there were no suspects, “but we have started investigations and are looking at a few possibilities to get leads”.

Police are studying security camera footage from the airport. Images circulating in the media have focused on two women seen alongside Mr Kim, who were later seen leaving the scene in a taxi.

Unnamed US government sources have said they believe he was poisoned by North Korean agents, but there has been no official comment from the White House.