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KUALA LUMPUR, Malaysia — North Korea lashed out at Malaysia over the death of Kim Jong Un's half-brother Thursday, in a searing diatribe that accused its ally of collaborating with South Korea to harm the regime.

The remarks were the first by North Korea's outspoken state-controlled news agency, KCNA, since the death of Kim Jong Nam in Kuala Lumpur on February 13.

It report railed at Malaysia’s government for performing an autopsy on the body of a North Korean citizen carrying a diplomatic passport.

"This proves that the Malaysian side is going to politicize the transfer of the body in utter disregard of international law and morality, and thus attain a sinister purpose," KCNA said.

Although Malaysian and South Korean officials have confirmed the dead man's identity, at no point did KCNA refer to him by name as Kim Jong Nam, the 46-year old half-brother of Kim Jong Un.

It claimed Malaysian authorities had at first told North Korea’s embassy that the man had died of an apparent heart attack.

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"The biggest responsibility for his death rests with the government of Malaysia, as the citizen of the DPRK died in its land," it added, using an acronym for the Democratic People's Republic of Korea, the North's official name.

Kim Jong Nam. AP

Earlier in the week, North Korea’s ambassador to Malaysia, Kang Chol, took the unusual step of speaking directly to the media to demand a joint investigation in the case, claiming the allegations of espionage and poisoning were a conspiracy hatched by South Korea.

Malaysia is among North Korea’s few friends, but the case has triggered a diplomatic meltdown which gained momentum Wednesday when police demanded to question a senior official at the embassyabout his possible involvement.

Police claim the diplomat, Hyon Kwang Song, who holds the position of second secretary, was spotted in airport security video the day Kim was killed. Another North Korean, who works for the state-owned Air Koryo airline, is also wanted for questioning.

North Korean Airlines employee (from left-to-right) Kim Uk Il, Ri Ji U and North Korean Embassy staff Hyon Kwong Song have all been identified for questioning in connection with the murder of Kim Jong Nam. Royal Malaysian Police via EPA

There are unconfirmed reports in the local and foreign media that both men are now hiding inside the North Korean embassy in Malaysia.

In total, eight North Koreans are being sought in connection with the case. At least four of them are believed to be back in Pyongyang, prompting authorities in Malaysia to file an alert with Interpol in an attempt to track them down.

A former North Korean diplomat, who defected to South Korea last year, believes the web of nationals involved can only mean that it all leads to the top in Pyongyang.

"Even if North Korea denies the assassination, one hundred percent it was ordered by Kim Jong Un," said Thae Yong Ho, in an interview with South Korean news channel YTN that was shared with NBC News.

"If it is confirmed that Kim Jong Nam has been murdered by North Koreans, this would be purely the result of Kim Jong Un’s paranoia," he said. "Efforts to make Kim Jong Nam [a] nobody already began in the early 1990s."

Thae was once North Korea’s deputy ambassador to the United Kingdom, but was denounced by the regime as a criminal and "human scum" when he defected to Seoul.

Malaysian police outside the North Korean Embassy in Kuala Lumpur on Thursday. Athit Perawongmetha / Reuters

As diplomatic tension ramps up, so does security at the morgue where Kim Jong Nam’s body remained Thursday. Plain-clothes policemen with automatic weapons slung around their shoulders paced the parking lot, keeping watch since an attempted break-in earlier in the week.

"We will not allow anyone to tamper with the mortuary," said Khaled Abu Bakr, inspector general of the Royal Malaysian Police. He said investigators knew who was behind the attempted break-in but did not say who.

For 11 days, forensics experts and police have waited for a relative to come forward with a DNA sample to confirm it really is the body of Kim Jong Nam. They have repeatedly refused to release the body to North Korean officials despite their demands to return it to Pyongyang.

Malaysian authorities have formally asked North Korea’s embassy to help get DNA from any one related to Kim Jong Nam, including his dictator half-brother, Kim Jong Un.