Malaysian police said Wednesday they have identified two additional North Koreans, including a diplomat, as suspects involved in the murder of the half brother of the North's leader Kim Jong-un.

Police said they identified a North Korean embassy official and an airline employee -- Hyon Kwang-song and Kim Uk-il -- as those that need to be questioned in relation to the death of Kim Jong-nam.

The diplomat holds the rank of second secretary at the North's embassy in Kuala Lumpur, while the airline employee is with Air Koryo, the communist country's flag carrier.

Kim Jong-nam was killed on Feb. 13 at an airport in Malaysia after being attacked by two Asian women with what appears to be a poisonous substance. He was waiting for a flight to his home in Macau.

"We have written to the ambassador to allow us to interview both of the newly identified people," national police Chief Khalid Abu Bakar was quoted as saying by AFP.

"We hope that the embassy will cooperate with us and allow us to interview them quickly. If not, we will compel them to come to us," the report said.

A total of eight North Koreans are suspected of being involved in the death. Police arrested Ri Jong-chol, a 46-year-old North Korean man, on Friday following the arrest of the two women.

Authorities here said that four North Koreans fled Malaysia on the day of Kim's death and are now believed to be in Pyongyang.

Three others, including the diplomat, are thought to be still in the Southeast Asian country.

Malaysia has asked Pyongyang to cooperate with its probe and return the four suspects, the police chief added.

He said that the two female suspects -- one from Vietnam and the other from Indonesia -- were aware that they took part in the attack and used their bare hands to wipe the toxic substance on his face.

"Yes, the two female suspects knew that the substance they had was toxic. We don't know what kind of chemical was used," the chief of police quoted as saying by Reuter, adding that there were instructed to wash their hands afterwards.

The female suspects claimed that they were deceived into thinking they were part of a comedy TV show.

Khalid said that no family member of the murdered Kim has yet come forward to claim his body. There were rumors that Kim Han-sol, Kim's son, probably arrived in Malaysia on Monday from Macau where his mother and sister are presumed to be hiding under China's protection. Previously, Malaysia gave two weeks for Kim's next-of-kin to come to claim his body.

Meanwhile, Doan Thi Huong, the Vietnamese suspect, visited South Korea in November last year, intelligence sources said.

"Her visit did not seem to be related to Kim's murder, but we are investigating the purpose of her trip and what she did in the country," an official said.

The latest incident has developed into a diplomatic row between Malaysia and North Korea, which have maintained a good diplomatic relationship for more than 40 years.

North Korean top envoy to Malaysia Kang Chol denounced Malaysia's probe results, claiming that Malaysia colluded with Seoul in investigating the case.

Malaysian Prime Minister Najib Razak denounced Kang's comment, stressing that the investigation would be fair.

"The statement by the ambassador was totally uncalled for. It was diplomatically rude. But Malaysia will stand firm," the prime minister was quoted as saying by Reuters.

South Korea's spy agency claimed North Korean ruler Kim Jong-un had issued a "standing order" to kill his estranged sibling since assuming power in late 2011.

Seoul said it is highly likely that North Korea is behind the death, adding that Pyongyang has a track record of committing terrorist attacks and inhumane acts.

Pyongyang, meanwhile, appears to have closely kept tabs on military officials regardless of their ranks since the 2011 death of former leader Kim Jong-il, according to a report by a group of North Korean defectors.

The report showed the repressive regime has monitored even the facial expression of military officials in what could be a move to glean evidence to carry out purges and even executions. (Yonhap)