Kuala Lumpur International Airport Terminal 2 was declared a "safe zone" on Sunday morning, after a detection operation found no trace of VX nerve agent, a lethal chemical weapon found on the body of a Democratic People's Republic of Korea (DPRK) man who died on Feb. 13.

During the operation, special personnel wearing protective clothes and masks used detector-like equipment to sniff certain areas at the self-check kiosks, the medical clinic, washrooms, the information counter and a restaurant, all areas in contact with the victim and the suspects.

As a highly stable substance, VX nerve agent is very difficult to evaporate, causing concerns that the airport's Terminal 2, which recorded a passenger traffic of more than 27 million in 2016, could pose a danger to passengers and tourists.

The operation was conducted to ensure the terminal is "free from contamination of any hazardous materials," Selangor police Abdul Samah Mat told reporters after the operation.

He said the personnel involved in the operation was comprised of a team from the police in charge of chemical, biological and radiological nuclear explosives, a team from the fire and rescue department tasked with handling hazardous materials and a team from the Atomic Energy Licensing Board.

Cops, medical staff and airport staff that had been in contact with the DPRK man were doing fine after medical examination was carried out, he said.

When asked about how the two female suspects, whom the police said used their bare hands to carry out the attack, survived after the attack, Samah said the police are still looking into that by doing some tests.

Samah also said the police has raided a condominium related to the four suspects who have fled Malaysia on the same day of the killing, and took some substance samples related to the case. He did not reveal what kind of samples were taken but said they have been sent to a chemistry lab for further analysis.

As for a DPRK embassy second secretary believed to be involved in the incident, Samah said the police will give him "a reasonable period" to show up, otherwise "we will move towards other provisions of the law that we have in this country to compel his presence."

The DPRK man died on the way from the Malaysian airport to hospital on Feb. 13.

Malaysian police identified him as Kim Chol from the DPRK.

Deputy Prime Minister Ahmad Zahid Hamidi said embassy documents showed the man was Kim Jong Nam, half-brother of the DPRK top leader Kim Jong Un, but the claim was denied by the DPRK ambassador in Malaysia.