North Korea said on Wednesday the claim that VX nerve agent was used to kill one of its citizens in Malaysia was "absurd" and lacked scientific basis, calling it an assertion made by the United States and South Korea to tarnish the North's image.

Last week, Malaysian police said VX nerve agent, a chemical classified by the United Nations as a weapon of mass destruction, was used to kill Kim Jong Nam, estranged half-brother of North Korean leader Kim Jong Un, on Feb. 13.

South Korean and U.S. officials have said they believe North Korean agents killed Kim Jong Nam.