Police chief Khalid Abu Bakar told a packed media conference that the two foreign women were aware they were using a poison on Kim at the Kuala Lumpur International Airport last week.

The duo are accused of acting under the instruction of four North Korean men, who were accompanying them at the incident place, and having been trained in how to apply and neutralize the toxic liquid.

Police say they were recorded practicing the act several times in the airport and at Kuala Lumpur’s city center.

The police findings contradict claims by the two suspects -- nationals of Vietnam and Indonesia -- who have said they thought they were pulling a prank on Kim, who died shortly after the alleged poisoning.

"Of course they knew. You have seen the video, she was moving her hand away from her body and walking to the bathroom,” Bakar said Wednesday.

"We strongly believe it is a planned thing and they have been trained to do that."

Police say they arrived at their conclusion after viewing security footage from various locations -- including two central shopping malls -- that reportedly showed the four North Koreans demonstrating ways to kill Kim to the two women.

Bakar said police will apply to extend the remand of the two women and one North Korean man for a further seven days.

He added that authorities are seeking North Korea's cooperation for the return of two citizens of the reclusive state wanted in Malaysia for the killing.

Bakar declined to comment on suspicions of direct involvement by North Korea in the death, but quickly added that evidence collected so far only showed the involvement of North Koreans.

Bakar identified one of the wanted individuals as the second secretary at the North Korean Embassy, Hyon Kwang Song, and Air Koryo airline employee Kim Uk II.

"We have written to the embassy to allow us to interview both of them. We hope that they [the embassy] will cooperate with us and allow us to interview them quickly, if not we will compel them," he told reporters.

He said if the suspected do not comply with police requests, arrest warrants would be issued for them to give statements to local police.

"Surely we know that we have the grounds to ask them to assist in the investigations... It is a crime committed in Malaysia," he said.