North Korea is conducting biological weapons experiments to test the possibility of loading anthrax-laden warheads on its intercontinental ballistic missiles, it has been reported.
Japan's Asahi newspaper reported citing an unidentified person connected to South Korean intelligence, that North Korea was conducting biological weapons experiments to test the possibility of loading anthrax-laden warheads on its intercontinental ballistic missiles, according to the Daily Mail.
The Asahi report said the US Government was aware of the tests, which were meant to ascertain whether the anthrax bacteria could survive the high temperatures that occur during warheads' re-entry from space.
North Korea vehemently denied the allegation and said it will "take revenge" on the US for saying it is developing biological weapons.
In a statement issued via the state Korean Central News Agency, the regime said it was party to the Biological Weapons Convention and as such "maintains its consistent stand to oppose development, manufacture, stockpiling and possession of biological weapons".
It went on that the more the US "clings" it its anti North Korea stance "the more hardened the determination of our entire military personnel and people to take revenge will be".
The news that North Korea may have been testing anthrax-laden warheads comes as South Korean President Moon Jae-in is seeking to soothe relations with China and the North before the Winter Olympics in South Korea in February.
He suggested he was prepared to postpone military drills with the United States.
Pyongyang sees the joint exercises as preparation for war, while Beijing is still angry about the deployment of a US anti-missile system, commonly known as THAAD, by South Korea.
China believes the system's powerful radar can see far into its territory, but Seoul argues it needs it to guard against the threat posed by North Korea's missile and nuclear programmes.
Seoul has proposed the potential delay in drills to Washington, which was also discussed during a summit last week between Moon and Chinese President Xi Jinping, an official from the presidential Blue House in Seoul said.
China has in the past proposed a "freeze for freeze" arrangement under which North Korea would stop its nuclear and missile tests in exchange for a halt to the exercises. However, Washington has rejected the idea and Pyongyang has shown little interest in negotiations.
US Secretary of State Rex Tillerson said in Ottawa he was unaware of any plans to "alter longstanding and scheduled and regular military exercises".
North Korea has stepped up its missile and nuclear tests to an unprecedented rate this year, and any new provocation from the North would "inevitably have an impact" on the exercises, the Blue House official said.
"It is a display of the president's strong message that North Korea must not conduct any provocation [during the Olympics]," the official told reporters.
North Korea has also been hit with increased international sanctions over its missile and nuclear tests this year.
The United States has given China a draft resolution for tougher UN sanctions on North Korea and is hoping for a quick vote on it by the UN Security Council, a Western diplomat said, however Beijing has yet to sign on.
Details of the draft given to China last week were not immediately available, but the United States is keen to step up global sanctions to pressure North Korea to give up a weapons programme aimed at developing a nuclear-tipped missile capable of hitting the United States.
China resumed some restrictions on group tours into the South, South Korea's inbound travel agency said.
What is anthrax and how can it be used as a weapon?
Anthrax is a disease caused by the organism bacillus anthracis.
It is possible to use anthrax as a military weapon by placing it in missiles, rockets or bombs.
Anthrax spores could also be released by planes which could spray it over large areas and once present the spores can remain dormant for decades.
The deadliness of an anthrax attack depends on the quantity of spores and the effectiveness of a delivery system.
An initial phase of flu-like symptoms can usually last for one to three days, before the patient enters a second phase of high fever, chest pains, severe breathing problems and shock. Death usually follows within two days.
A wave of attacks occurred in the US in late 2001 with the spores placed in envelopes which killed five people.
The first mass use of anthrax spores as a weapon in war is said to have taken place during the Japanese occupation of China from 1932 to 1945.
The Japanese allegedly experimented with the use of anthrax and other biological weapons in Manchuria, and some 10,000 deliberately infected prisoners are thought to have died as a result.
Britain experimented with anthrax as a weapon in the 1940s and the US made some for military use in the 1950s and 1960s.
The Soviet Union also weaponised anthrax and Iraq admitted to doing so in 1995.
The World Health Organisation estimated that, should 50kg of anthrax be released from an aircraft over an urban population of five million, there would be 250,000 cases of the disease.