North Korea has accused the US and South Korea of attempting to assassinate leader Kim Jong Un with a "bio-chemical substance."

In an extraordinary 1,800-word report Friday, North Korean state news agency KCNA said a "hideous terrorist group" conspired with the CIA and South Korea's Intelligence Service (IS) to "commit bomb terrorism targeting the supreme leadership" during major events including a recent military parade.

The report claimed a North Korean citizen was involved in the plot, using "biochemical substances including radioactive substance and nano poisonous substance" to target Kim.

The KCNA report claimed the plot was "recently uncovered and smashed," and accused members of the CIA and IS of working with a North Korean citizen to provide money and weapons to carry out "state-sponsored terrorism."

A similar charge was laid against Pyongyang by Seoul in February following the murder of Kim Jong Nam, allegedly at the hands of North Korean agents.

The half-brother of Kim Jong Un was poisoned with the VX nerve agent while in Kuala Lumpur airport and died en route to a hospital.
North Korea has repeatedly denied any involvement in Kim's death.