Preliminary analysis from the Chemistry Department of Malaysia revealed that an extremely toxic chemical substance was used in the murder of Kim Jong-nam, the estranged half-brother of North Korean leader Kim Jong-un.

"The Royal Malaysian Police has received the preliminary report from the Chemistry Department of Malaysia, with regard to the death of a North Korean national recently.

"The chemical substance on the exhibits has been identified as ethyl s-2-diisopropylaminoethyl methylphosphonothiolate, or 'VX nerve agent'.

"VX is listed as a chemical weapon under schedule 1 of the Chemical Weapons Convention Act 2005 and Chemical Weapons Convention (CWC) 1997," the inspector-general of police (IGP) Khalid Abu Bakar said in a statement today.

According to Reuters, VX is tasteless and odourless, and is outlawed under the Chemical Weapons Convention, except for "research, medical or pharmaceutical purposes".

It can be manufactured as a liquid, cream or aerosol. Absorbed in large doses, it is fatal after 15 minutes, according to the US Army's Edgewood Chemical Biological Center, making it the most toxic known nerve agent in the world.

Jong-nam died at KLIA2 airport terminal on Feb 13 after two unidentified women had purportedly sprayed or wiped his face with a liquid that had left him feeling ill.

Khalid added that the preliminary analysis, carried out by the Centre for Chemical Weapons Analysis of the Chemistry Department, involved dry swabs of the face and eye mucosa.

Other exhibits are still under analysis, he said.

Separately, deputy inspector-general of police Noor Rashid Ibrahim said Jong-nam's kin is expected to arrive in Malaysia by Saturday, according to The Star.

So far, none of Jong-nam's relatives have come forward to identify the body or undergo a DNA test, said Noor Rashid.

“Either his children or a close relative will come, and we will wait for their arrival,” he said.

Noor Rashid did not confirm whether it would be Jong-nam's eldest son, 22-year-old Kim Han-sol.

On Monday night, the press congregated at KLIA2 over rumours that Han-sol would be arriving that night, though they were ultimately unable to confirm his arrival.

On Feb 13, it was reported that Jong-nam was at KLIA2 to board a flight to Macau when he was allegedly poisoned by two women.

Jong-nam, who was using the name Kim Chol on his passport, reportedly died on the way to Putrajaya Hospital shortly after.