Malaysian police are looking for four North Korean men aged between 33 and 57 suspected of involvement in Monday's apparent assassination of Kim Jong-nam , deputy national police chief Noor Rashid Ibrahim told a press conference on Sunday.

He said all four men had left the country the same day as the incident, in which Kim, the half-brother of North Korean leader Kim Jong Un, died after an unidentified liquid was sprayed in his face at Kuala Lumpur International Airport. He said they were all traveling on normal passports, not diplomatic ones.

He also identified a fifth person of interest and showed photographs of two more North Koreans also wanted by Malaysian authorities in connection with the killing.

Four people - a woman carrying a Vietnamese passport, an Indonesian woman, a Malaysian man and a North Korean man - have already been detained.

Seoul claims the attack was carried out by female agents at the order of Pyongyang.

Diplomatic spat

North Korea has demanded the return of the body, but Malaysia has said it must remain in the country until it is identified by means of DNA from a family member. Police said on Sunday that no family member had so far come forward.

The exact cause of death has not yet been established.

South Korean intelligence officials maintain that Kim Jong Un and Kim Jong Nam had a troubled relationship, with the North Korean leader suspicious of the fact that Beijing allowed his older half-brother to live in its autonomous territory of Macau.

Their alleged rivalry could also derive in part from the fact that Kim Jong Nam, also the oldest son of late President Kim Jong Il, was originally the heir-apparent in Pyongyang, though he later fell out of favor.

tj/rc (AFP, AP, Reuters)