Expelled North Korean Ambassador Kang Chol left Kuala Lumpur yesterday evening, but not before Pyongyang, in a tit-for-tat move, gave his Malaysian counterpart 48 hours' notice to leave the country.

The expulsions resulted from an ongoing spat over the murder of Mr Kim Jong Nam, the estranged half- brother of North Korea's leader.

Malaysian investigators say a North Korean national was poisoned with a deadly nerve agent at the KL airport on Feb 13, just before boarding a flight to Macau. South Korea and the United States allege that North Korea ordered the assassination of Mr Kim.

But North Korea has insisted the dead man is Kim Chol, the name given in his diplomatic passport, and claimed he died of a "heart stroke". It refused to accept the findings of a Malaysian autopsy, which stated the cause of death to be poisoning.

Prime Minister Najib Razak said yesterday that Mr Kang should have apologised for accusing the Malaysian government of subverting investigations and colluding with North Korea's enemies, and that his failure to do so was what led the Malaysian authorities to issue a 48-hour notice of expulsion on Saturday.

"Based on principles, we have declared him persona non grata. No one should disrupt us as they please," Datuk Seri Najib told reporters after the opening of this year's parliamentary session.

North Korea's state-run agency KCNA reported yesterday that Malaysia's ambassador had been declared persona non grata and would have to leave "within 48 hours from 10am on March 5".

However, Ambassador Mohamad Nizan Mohamad has already returned to Malaysia, after he was recalled about two weeks ago.

Mr Kang, who arrived at the airport just before the 6pm deadline to exit the country, said through a translator that the statements he had made were "an expression of the righteous stand" of North Korea on the "pre-targeted investigation".

"I express grave concern over the extreme measures by the Malaysian government, doing great harm to bilateral relations which have a history of over 40 years," he said, after reiterating that Mr Kim's autopsy had been done without the consent or presence of North Korean officials, and the claim that one of North Korea's citizens was arrested without proof of his involvement.

Mr Ri Jong Chol was deported at the end of a two-week remand period last Friday, after prosecutors said they could not find sufficient evidence to charge him in connection with Mr Kim's murder.

Two women - Indonesian Siti Aisyah, 25, and Vietnamese Doan Thi Huong, 28 - were charged with Mr Kim's murder last Thursday.

Amid the tensions, Malaysia announced that its national football team would not travel to North Korea for an Asian Cup qualifier on March 28 because of safety concerns. It asked the Asian Football Confederation to allow the match to be played at a neutral venue.

Asked whether Malaysia would review ties with North Korea, Mr Najib said yesterday that "we will take it one step at a time", while Deputy Foreign Minister Reezal Merican told reporters that ties "will never be the same again".

Health Minister Subramaniam Sathasivam also rubbished North Korea's claim that Mr Kim's death was due to heart problems. "Based on the autopsy findings, there was no heart attack," he said.