Kim Jong Un’s estranged half-brother was killed with a highly toxic weapon of mass destruction — known as VX nerve agent, police say.

Malaysian authorities revealed the name of the chemical that took Kim Jong Nam’s life last week in a press release early Friday local time, saying the Centre of Chemical Weapons had identified it during its preliminary analysis.

Officials said they had swabbed Jong Nam’s face and eyes and found the notorious warfare agent — also known as ethyl N-2-diisopropylaminoethyl methylphosphonothiolate.

The United Nations and the Centers for Disease Control and Prevention both classify the oily substance as a weapon of mass destruction. The human-made liquid was first developed in the United Kingdom in the early 1950s, according to the CDC.

It is completely odorless and tasteless — and can be administered through skin contact, eye contact or inhalation.

Jong Nam, 45, was ambushed Feb. 13 by a pair of female assassins who used nothing but their bare hands to fatally poison him. Authorities have said the VX nerve agent was placed on them by a North Korean man, who is now in custody, along with the two women.

The highly toxic, fast-acting agent ultimately kills someone by disrupting the transmission of nerve impulses in the nervous system, the CDC reports.

Symptoms — such as increased salivation, constricted pupils, blurred vision and tightness of the chest — are known to appear within a few seconds after exposure.

As is the case with most nerve agents, VX affects the acetylcholinesterase enzyme, which serves as the “off switch” for the body’s glands and muscles. Once exposed, a person’s molecules would constantly be stimulated — causing their muscles to spasm and eventually tire.

The end result is typically death by asphyxiation or heart failure.

“It is possible that any visible VX liquid contact on the skin, unless washed off immediately, would be lethal,” the CDC says on its website. “Even a tiny drop of nerve agent on the skin can cause sweating and muscle twitching where the agent touched the skin.”

VX — which is outlawed under the Chemical Weapons Convention — allegedly was used by Saddam Hussein during the Iran-Iraq War, and many believe there may be stockpiles of the substance in Syria today.

It is currently the most toxic nerve agent known in the world.

With Post wires