Malaysian police said that a nerve agent has been used during the attack on Kim Jong Nam, the half-brother of the DPRK's leader Kim Jong Un, at a Kuala Lumpur airport on February 13.

The substance has been identified as VX, according to a preliminary analysis report by the Center for Chemical Weapons of the country’s Chemistry Department released on Friday morning.

VX is an extremely toxic substance that is odorless and tasteless, which has been classified by the UN as a chemical weapon.

Traces of VX have been detected on swabs of Kim’s face and eyes, according to the report.

Surveillance footage on February 13 shows Kim being attacked from the back at the airport as a woman rushed up to him from behind and smudged her hand on his face. Another woman was also spotted at the scene a few moments before the accident, and both women walked off calmly afterwards, leaving a startled Kim behind. In another clip, Kim could be seen walking up to an airport staff, asking apparently for help, and being directed to an on-site clinic.

The police said that Kim suffered a seizure and died on his way to the hospital.

Heart attack has been ruled out by Malaysian police as a death cause.