According to North Korean state media report, US and South Korean agents are plotting to kill North Korean leader Kim Jong-un.
Following a statement by the ministry of state security, a “terrorist group” backed by the CIA and South Korea’s intelligence agency had entered the country in order to prepare an attack with a bio-chemical substance.
It said North Korea would find and “mercilessly destroy” the terrorists.
The claims come amid high tensions in the region.
US President Donald Trump has promised to “solve” North Korea and stop it developing nuclear weapons.
‘Nano Poisonous Substance’
The statement, carried by North Korean news agency KCNA, said the CIA and South Korean intelligence services had “hatched a vicious plot to hurt the supreme leadership of the DPRK”.
It did not mention Kim Jong-un by name, but he is widely referred to as the Supreme Leader.
The plot included the use of “biochemical substances including radioactive substance and nano poisonous substance” whose results would “appear after six or twelve months”, the statement said.
The ministry alleges that a North Korean, which it identifies only by the surname “Kim”, had been “corrupted and bribed” by South Korean intelligence services while he was working in Russia.
It lists several alleged payments made to him, amounting in total to nearly $300,000, and says on his return to Pyongyang he was instructed to provide detailed information about a frequently used event ground and to assess possible methods of attack.
“Korean-style anti-terrorist attack will be commenced from this moment to sweep away the intelligence and plot-breeding organisations of the US imperialists and the puppet clique,” the statement says.
A war of words between the West and Pyongyang has escalated in recent weeks, with North Korea threatening to carry out a sixth nuclear test.
On Saturday North Korea conducted its second failed ballistic missile test in two weeks.
The US has sent a warship to the region and installed a controversial anti-missile defence system in South Korea.