North Korea has blamed Malaysia for the death of Kim Jong-nam, the estranged half-brother of the country's leader Kim Jong-un, at the Kuala Lumpur International Airport 2.

"The biggest responsibility for his death rests with the government of Malaysia as the citizen of the DPRK [Democratic People's Republic of Korea], died in its land," North Korea's state-run news agency KCMA said.

The authoritarian regime has also accused the Malaysian government of having an "unfriendly attitude" following the murder of the 45-year-old. The agency, did not name Jong-nam in its report, only referring to him as "a citizen of the DPRK."

KCNA claimed Malaysia initially informed North Korea that Jong-nam had died of a heart attack, according to Reuters.

The agency, quoting a spokesman for a state committee, claimed that Malaysia changed its stance on the incident after reports surfaced in Seoul that Jong-nam was poisoned. The US and South Korean officials believe Jong-nam was killed by North Korean operatives,

"What merits more serious attention is the fact that the unjust acts of the Malaysian side are timed to coincide with the anti-DPRK conspiratorial racket launched by the South Korean authorities," the report said.

Malaysian investigators have named five suspects, all from the secretive state, with four people so far arrested.

Jong-nam was waiting to board a flight to Macau on 13 February, when he he was allegedly poisoned by two women.

CCTV footage suggests he became unwell after two suspects appeared to wipe a cloth on his face. He died on the way to hospital.

Kim Jong Nam
File photo: Kim Jong Nam arrives at Beijing airport in Beijing, China on 11 February 2007 Kyodo/Reuters

Pyongyang has denied the person who died was indeed Jong-nam and North Korea's embassy in Malaysia is also calling for the immediate release of the two "innocent women" detained following the incident.

Malaysia's police chief Khalid Abu Bakar had said that the two women had coated their hands with toxic chemicals and then wiped them on Jong-nam's face, something Pyongyang has mocked.

Authorities said that they were searching for a senior North Korean embassy official Hyon Kwang song, 44, and North Korean airline Air Koryo staffer called Kim Uk-Il after the incident.

A Vietnamese woman, an Indonesian woman, a Malaysian and a North Korean chemist are also in custody. Police have stated that they are looking for up to seven other suspects.

Kim Jong Nam
The detained suspects from left, clockwise: Vietnamese Doan Thi Huong, North Korean Ri Jong Chol, Malaysian Muhammad Farid Bin Jallaludin, Indonesian Siti Aisyah Royal Malaysia Police/Reuters

Pyongyang has proposed the idea of a joint investigation between the two nations by sending a delegation of jurists to "conclude the investigation into the incident in a fair way". Malaysia has dismissed this request.

In the days since the incident, Malaysian police have tightened security at the hospital mortuary where Jong-nam's body is being kept after a number of break-in attempts.

Malaysian authorities had turned down North Korea's repeated demands to send the body to Pyongyang amid rumours that Kim Jong-un was behind the assassination. They had said the body would only be handed over to the exiled North Korean's next-of-kin.