Military experts have warned Kim Jong-un is not only pursuing a nuclear missile programme but also developing bio-chemical weapons amid fears of World War 3 breaking out.

Kim is said to have a stockpile of the bubonic plague and it is believed Pyongyang could launch germ warfare in just 10 days, the Daily Star has claimed.

Pathogens stockpiled by Kim includes Smallpox, Anthrax, Yellow Fever, Typhoid and Chlorea, South Korea’s defence ministry believes.

North Korea has previously denied any existence of a bioweapons programme.

Defence experts warned in a paper published by the Belfer Centre at Harvard University that countering North Korea’s biological and chemical programmes was “urgent and necessary”.

It is thought North Korea would deploy a biological attack using missiles, drones, planes and rocket launches.

Aircraft could fly like crop sprayers dousing cities in airborne disease, or fired in short-range rockets across the border.

The report said: “North Korea is likely to use biological weapons before or at the beginning of a conflict to disrupt society and create panic, incapacitate societies, and/or cause a significant military diversion.

“If used on a large scale, these weapons can cause not only tens of thousands of deaths, but also create panic and paralyse societies.

“Nevertheless, the vividness of the nuclear threat has overshadowed other weapons programs, limiting the attention and policy input that they deserve.”

North Korea’s chemical weapons are believed to have been used to kill Kim Jong-nam, with Kim’s brother being smeared with the VX nerve agent in Malaysia.

The academic paper – titled The Known and Unknown – was published last month amid growing tensions between North Korea and the United States.

It said: “The goal of the international community should be to simultaneously gather more information about North Korea’s BW capability and reduce this threat posed by North Korea.

“It should not be comforted by the scarcity of information on the program, but should instead redouble efforts to better understand the threat and prepare to respond to it.”

North Korea has repeatedly traded sabre-rattling threats with the US in recent months amid a series of nuclear missile tests. 

Kim is said to be developing a missile capable of striking the US mainland. 

But his attention to germ warfare comes as Madagascar suffers an outbreak of the plague which the World Health Organisation is trying to contain. 

140 people have died in the outbreak of the pneumonic plague since August.