North Korea will "categorically reject" Malaysia's autopsy report on the death of the man identified by Malaysian authorities as the estranged half-brother of North Korean leader Kim Jong-un.
Kim Jong-nam died in Kuala Lumpur this week after being assaulted at Kuala Lumpur International Airport with what was thought to be a fast-acting poison. South Korean and US officials have said he was assassinated by North Korean agents.
In its first comments since the man's death, the North Korean envoy, Kang Chol, demanded that his body be released immediately.
"The Malaysian side forced the post-mortem without our permission and witnessing," Mr Kang told reporters outside the hospital late on Friday. "We will categorically reject the result of the post mortem."
He also accused Malaysia of "concealing something" and "colluding with outside forces".
His statement made no reference to the identity of the man.
Malaysia's top cop was firm on the autopsy.
"We have rules in Malaysia. Whilst in Malaysia, everyone has to obey and follow our rules and regulations," Inspector General of Police Khalid Abu Bakar told Reuters. "That includes North Korea."
Malaysian police said on Friday it would not release the body until it receives DNA samples from his next-of-kin.
North Korea rejected Malaysia's request for a post-mortem, because "he is a diplomatic passport holder and our citizen who is under the consular protection of the DPRK", Kang said, adding that Malaysia had initially said the North Korean died from a heart attack.
Two female suspects, one an Indonesian and the other carrying Vietnamese travel documents, have been arrested in connection with the murder.
A Malaysian man has also been detained. Four men believed to have been accomplices are still being sought.
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 the isolated, nuclear-armed North Korea.