Malaysia expelled the North's ambassador for raising the unfounded accusations, and the North responded by kicking out Malaysia's ambassador to Pyongyang.

Earlier Tuesday, the North's Foreign Ministry said the country will not allow Malaysians staying in the North to leave the country temporarily. In a tit-for-tat response, Malaysia also said that North Korean Embassy staff are barred from leaving the country.

Malaysian police have determined that the lethal nerve agent VX was used, adding to mounting evidence that the North was behind the killing. VX is a chemical agent listed as a weapon of mass destruction by the United Nations and its use is banned under the Chemical Weapons Convention.

Eight North Koreans have been named as suspects, but the North has denied its involvement. (Yonhap)