North Korean ambassador faces deadline to leave Malaysia in Kim row

"I think we have given a clear message to the North Korean government that we are serious about solving this problem and we do not want (the investigation) to be manipulated," deputy prime minister Ahmad Zahid Hamidi was quoted as saying.

The death of Mr Kim, the estranged half brother of North Korean leader Kim Jong Un, has unleashed a diplomatic battle between Malaysia and North Korea.

Malaysian authorities said he died within 20 minutes after two women at Kuala Lumpur airport smeared his face with VX, a banned nerve agent considered a weapon of mass destruction.

North Korea has rejected Malaysia's post-mortem finding that VX killed Mr Kim. Mr Kang has accused the Malaysian government of trying to hide something and said it colluded with outside powers to defame North Korea.

His expulsion came days after Malaysia said it would scrap visa-free entry for North Koreans.

Ri Tong Il, a former North Korean deputy ambassador to the United Nations, has said Mr Kim probably died of a heart attack because he suffered from cardiac disease, diabetes and high blood pressure.

Two women - one Indonesian, one Vietnamese - have been charged with murder, although both reportedly say they were duped into thinking they were playing a harmless prank.

Authorities released a North Korean chemist, Ri Jong Chol, from custody on Saturday due to a lack of evidence to charge him and deported him on the same day. He has accused Malaysian police of threatening to kill his family to coerce him into confessing to the crime.

Malaysia is also looking for seven other North Korean suspects, four of whom are believed to have left the country on the day of the killing. Three others, including an official at the North Korean embassy and an employee of Air Koryo, North Korea's national carrier, are believed to still be in Malaysia.

Malaysia's finding that VX killed Mr Kim boosted speculation that North Korea orchestrated the attack.

Experts say the oily poison was almost certainly produced in a sophisticated state weapons laboratory, and North Korea is widely believed to possess large quantities of chemical weapons, including VX.

Pyongyang is trying to retrieve the body, but has not acknowledged that the victim is Kim Jong Un's half brother, as Malaysian government officials have confirmed.

A lawyer for the Vietnamese woman accused of poisoning Mr Kim said there were serious holes in the case.

Selvam Shanmugam, who represents Doan Thi Huong, told Vietnam's state-run online newspaper Zing that allegations that the North Korean man had existing health problems should be cause for a new post-mortem.

"There were reasons for the North Korean ambassador to say so. I believe that there are issues that the Malaysian attorney general has to consider," Mr Shanmugam was quoted as saying.

He questioned why, if VX was used, the two women were not harmed, or anyone else at the airport.

"Was it the toxic VX agent or Kim Chol's illnesses?" he asked of the possible reasons for his death.

AP