It comes amid a deepening diplomatic row over the February killing of North Korean leader Kim Jong Un's half-brother at Kuala Lumpur International Airport 2.
"What we are facing now is the result of their action in assassinating their own citizen in Malaysia, on Malaysian soil, using a strictly banned chemical weapon," Najib told state media agency Bernama Wednesday.
A press official for Najib confirmed the comments to CNN. North Korea has repeatedly denied any involvement in Kim Jong Nam's murder.
