Last month, Kim Jong-nam, the half brother of the North Korean leader was murdered in Kuala Lumpur International Airport after two women rubbed the lethal chemical on his face. The Malaysian police later concluded several North Korean men, including a Malaysian-based diplomat, were behind the killing.

Over one month following the killing, however, the international community has yet to take concerted action to punish the regime for the use of the chemical classified as a weapon of mass destruction.

Bennett said North Korea does not consider the use of chemical weapons as WMD. "They believe it's a conventional weapon. That's a big thing to recognize."

For that reason, he said, "We need to be trying to establish it in the international community. We should be clearly pushing an action on the use of VX."

"We need to be setting a precedent that this is unacceptable in the international community," Bennett stressed in the lecture focused on North Korean security challenges.

Drawing on a growing South Korea-China diplomatic feud over Seoul's deployment of an advanced anti-missile system known as THAAD, the senior researcher said that the Asian power is trying to tame the bilateral relationship.

"China's objective with THAAD is not just prevent THAAD deployment. I think it has longer-term influence kind of approach that they are trying to develop a precedent that if we tell Korea to do something, Korea realizes it's going to be too costly if it doesn't do that."

"China's whole point of putting pressure on THAAD is to demonstrate to everyone around the world that there will be a price to pay if they choose to cause problems for China," he said.

Over the past months since South Korea and the US officially decided to bring in the missile interceptor to deter North Korea's nuclear and missile threats in mid-2016, China has taken a series of crushing economic retaliations against Seoul, demanding the withdrawal of the deployment which Beijing says seriously compromises its security interests.

Bennett also said North Korea is believed to be in possession of as many as 50 nuclear weapons as of now, indicating that North Korea's increased nuclear threats demand a different policy approach from South Korea and the US.

Former US President Barack Obama had been against the use of nuclear weapons in any case, but, Bennett said, "I don't think the (Donald) Trump administration has the same kind of approach" although exactly what Trump's North Korea policy would be is still unknown. (Yonhap)