North Korea has rejected a Malaysian autopsy finding that VX nerve agent killed Kim Jong Nam, saying he probably died of a heart attack because he suffered from heart disease, diabetes and high blood pressure.
The death of Kim, the estranged half brother of North Korea's ruler, has unleashed a diplomatic battle between Malaysia and North Korea.
The autopsy is especially sensitive because North Korea had asked Malaysia not to perform one, but authorities carried it out anyway, saying they were following the law.
Also on Thursday, amid growing fallout from the killing, Malaysia announced it is scrapping visa-free entry for North Koreans.
Malaysian officials say two women smeared VX nerve agent - a banned chemical weapon - on Kim's face as he waited for a flight at Kuala Lumpur's airport on February 13. Kim died within 20 minutes, authorities say. No bystanders reported falling ill.
The women, who were caught on grainy surveillance video, have been charged with murder. Both say they were duped into thinking they were playing a harmless prank.
Malaysia's autopsy finding that VX nerve agent killed Kim boosted speculation that North Korea orchestrated the attack. Experts say the oily poison was almost certainly produced in a sophisticated state weapons laboratory. North Korea has denied any role and accused Malaysia of bias.
Yesterday, Ri Tong-il, the former North Korean deputy ambassador to the United Nations, told a news conference that it made no sense to say the two women used such a deadly toxin without also killing or sickening themselves and people around them.
Ri said Kim had a history of heart problems and had been hospitalised in the past. He said he understood that Malaysian officials found medication for diabetes, heart problems and high blood pressure in Kim's belongings and concluded he wasn't fit to travel.
"This is a strong indication that the cause of death is a heart attack," Ri said.
North Korea does not acknowledge that it was Kim Jong Nam who died. Instead, it refers to the victim as Kim Chol, the name on the diplomatic passport he was carrying.
National police chief Khalid Abu Bakar brushed off Ri's claim of a heart attack.
"We have our experts who are qualified to determine the cause of death of Kim Chol. Our investigations, supported by expert reports, confirmed that Kim Chol was murdered. North Korea can say what they like but the facts remain," Khalid told AP.
Malaysian police said the attackers knew what they were doing and had been trained to go immediately to the bathroom and wash their hands. Police can't confirm whether the two women may have been given antidotes before the attack.
It comes as Deputy Prime Minister Ahmad Zahid Hamidi said the visa-free arrangement with North Korea will be scrapped starting on Monday for national security reasons.
He also slammed the North Korean ambassador in Kuala Lumpur, who has accused Malaysia of "trying to conceal something" and "colluding with hostile forces."
"We don't want to make enemies, but if they had used Malaysia for their own agenda, they should not accuse Malaysia and tarnish our image on the international stage," Zahid said. "We will act firmly to guarantee the safety of our people. Don't ever use Malaysia as a base to do anything you like."