Malaysia's investigation into the murder of the North Korean leader's half-brother shows that the Pyongyang government was behind the assassination, South Korea has said.
Malaysian police have arrested one North Korean suspect and are seeking four more North Koreans who left the country last Monday, the day Kim Jong-Nam was poisoned at Kuala Lumpur's main airport.
"Based on various factors, our government is certain that the dead man is Kim Jong-Nam, and considering that the five suspects are North Korean nationals, we view that the North Korean government is behind the incident," said Seoul's unification ministry spokesman Jeong Joon-Hee.
Mr Jeong declined to provide further details, citing the continuing investigation in Malaysia.
"As North Korea has been committing inhumane crimes and acts of terror, we are keeping a close eye on the latest incident with grave concern," he said.
Kim Jong-Nam, the half-brother of leader Kim Jong-Un, died after an unidentified liquid was sprayed in his face at Kuala Lumpur International Airport.
Seoul says the attack was carried out by female agents on Pyongyang's orders.
Malaysian police arrested a North Korean man on Friday in connection to the murder while a Vietnamese woman and an Indonesian woman have also been arrested.
A Malaysian man is being detained to facilitate the investigation.
"I can confirm today that they (four North Korean suspects) have left our country the very same day the incident happen," deputy inspector-general of police Noor Rashid Ismail told reporters at a press conference.
"The four suspects are holding normal passports, not diplomatic passports," he said.
"Next plan is to get them. We of course have international cooperation especially with Interpol, bilateral involvement with the country involved, we will go through those avenues to get the people involved."
Malaysian police said the cause of death was still not known and that they were waiting for pathology and toxicology tests after conducting a post-mortem.
A diplomatic spat between North Korea and Malaysia over the body has escalated.
North Korea has said it would reject Malaysia's autopsy report and accused Malaysia of "colluding with outside forces" - a veiled reference to rival South Korea.
The Malaysian police said they were trying to contact the next-of-kin of Kim Jong Nam.
"The body must be identified. The most eligible to identify the body physically is the next-of-kin," Noor Rashid said.
"We will verify again through scientific means, so it is very important for close family members to come forward to assist us in process of identification base on legal procedures under Malaysian law."
Police are giving the next-of-kin two weeks to claim the body.
South Korea's intelligence agency told politicians in Seoul that Mr Kim had been living with his second wife in the Chinese territory of Macau, under China's protection.
Kim Jong Nam, the eldest son of the late North Korean leader Kim Jong Il, had spoken out publicly against his family's dynastic control of isolated, nuclear-armed North Korea.
The young, unpredictable North Korean leader had issued a "standing order" for his elder half-brother's assassination, and that there had been a failed attempt in 2012.
