KUALA LUMPUR, Malaysia >> Malaysia is protecting its “sovereignty and dignity” by expelling the North Korean ambassador, the prime minister said Monday, as relations between the countries unraveled further over the poisoning of Kim Jong Nam, the estranged half brother of North Korea’s leader.

The bizarre murder case — and the ensuing diplomatic battle — appear to have cost North Korea one of its few friends in the international community.

Just hours after the North Korean ambassador headed to the airport to leave Malaysia, North Korea responded in kind, announcing that it was ordering Malaysia’s envoy out of Pyongyang. But the move was symbolic. Malaysia had already recalled its diplomat shortly after the killing.

In an attack many believe was orchestrated by North Korea, Kim Jong Nam died less than 20 minutes after two women wiped VX nerve agent on his face at Kuala Lumpur airport on Feb. 13, authorities say. The women, one from Vietnam and one from Indonesia, have been charged with murder.

North Korea has denied any role in the killing and accused Malaysia of conspiring with its enemies. North Korean Ambassador Kang Chol rejected a Malaysian autopsy that found Kim was killed with VX, a banned chemical weapon.

On Monday, Prime Minister Najib Razak said the decision to expel Kang sent a clear message.

“It means that we are firm in defending our sovereignty and dignity,” Najib said. “Don’t ever insult our country and don’t try to cause disruptions here.”

Malaysian authorities declared Kang “persona non grata” on Saturday and gave him two days to leave the country. He arrived late Monday afternoon at the Kuala Lumpur airport, where he told reporters that Malaysia was doing “great harm” to the countries’ relations.

Soon after, North Korea’s official Korean Central News Agency said Malaysia’s ambassador would also be expelled.

Malaysia’s Foreign Ministry spokesman, Raja Nushirwan Zainal Abidin, said North Korea’s decision to expel the Malaysia envoy had been expected.

“This reciprocal action is normal in diplomacy,” he said, adding that the envoy had been recalled two weeks ago for consultations and was still in Kuala Lumpur.

Malaysia’s finding that VX killed Kim boosted speculation that North Korea was behind 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.

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

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

Health Minister Subramaniam Sathasivam said pathologists have ruled that out.

“We are saying, based on autopsy findings, there was no heart attack,” he told reporters at Parliament.

Still, a lawyer for the Vietnamese suspect said news of existing health problems should be cause for a new autopsy. He also claimed that Malaysian pathologists do not have expertise in VX.

“I am writing to the attorney general tomorrow for a second post-mortem,” attorney Selvam Shanmugam, who represents Doan Thi Huong, said Monday outside the Vietnamese Embassy in Kuala Lumpur.

“They should have a foreign forensic (team) to participate in the post-mortem,” he said.

The two women accused of poisoning Kim say they were duped into thinking they were taking part in a harmless prank.

Malaysia is looking for seven North Korean suspects, four of whom are believed to have left the country on the day of the killing. The 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.

North Korea has a long history of ordering killings of people it views as threats to its regime. Kim Jong Nam was not known to be seeking political power, but his position as eldest son of the family that has ruled North Korea since it was founded could have made him appear to be a danger.

Also Monday, the fallout from the diplomatic battle reached the sports field.

Citing security concerns, Malaysia won’t allow its national soccer team to travel to North Korea for a qualifying match for the 2019 Asian Cup, the Football Association of Malaysia said. Malaysia was due to play North Korea on March 28.

Kang Chol’s expulsion “made the current situation unsafe for Malaysians to travel to North Korea,” said the association’s secretary-general, Hamidin Mohamad Amin. The association has asked the Asian Football Confederation to shift the venue from Pyongyang to a neutral arena.