Two women accused of murdering the estranged half-brother of North Korea's leader must have been trained to carry out "an assassination" using the deadly VX nerve agent, Malaysian prosecutors said as they wrapped up their case on Thursday.

Indonesian Siti Aisyah and Vietnamese Doan Thi Huong were charged with having common intent, with four North Korean fugitives, to kill Kim Jong Nam at Kuala Lumpur International Airport in February 2017.

Kim's face was smeared with VX, a banned nerve agent developed as a chemical weapon.