North Korea has threatened to launch a series of retaliations on the US and South Korean intelligence agencies after an alleged assassination attempt on its leader, Kim Jong-Un.

The country’s military will begin "a series of more powerful anti-terrorism striking actions and mercilessly destroy the terrorists”, said an English-language statement carried by the state-run Korean Central News Agency.

It went on to accuse the two countries of trying to kill the North Korean dictator with “biochemical substances” during a parade in the country's capital Pyongyang, celebrating the Day of the Sun, which commemorates the birth of North Korea's founder, Kim Il-Sung.

The administration also claimed that the CIA bribed a North Korean citizen $40,000 (£32,000) to carry out the assassination.

Ri Byong Ho, the North Korea head of intelligence, said the suspect was a "very important person" and that "there have already been more than 80 planned terrorist attacks" that have been foiled.

In retaliation, North Korea is undertaking "counter-terrorism measures of justice," he added.

No proof has been provided to back up the claims.

In pictures: North Korea military drill Show all 8 1 /8 In pictures: North Korea military drill In pictures: North Korea military drill North Korea's leader Kim Jong Un watches a military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) is seen in this handout photo by North Korea's Korean Central News Agency (KCNA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) is seen in this handout photo by North Korea's Korean Central News Agency (KCNA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) KCNA/Handout via REUTERS In pictures: North Korea military drill This image made from video of still images broadcast in a news bulletin by North Korea's KRT, shows what was said to be a 'Combined Fire Demonstration' held to celebrate the 85th anniversary of the North Korean army, in Wonsan, North Korea. KRT via AP Video In pictures: North Korea military drill This image made from video of still images broadcast in a news bulletin by North Korea's KRT, shows what was said to be a 'Combined Fire Demonstration' held to celebrate the 85th anniversary of the North Korean army, in Wonsan, North Korea. KRT via AP Video In pictures: North Korea military drill This image made from video of still images broadcast in a news bulletin by North Korea's KRT, shows what was said to be a 'Combined Fire Demonstration' held to celebrate the 85th anniversary of the North Korean army, in Wonsan, North Korea. KRT via AP Video

The CIA have not yet commented on Pyongyang's allegations.

In what appears to be a separate incident, the North Korean government detained a US citizen over the weekend, on suspicion of acts against the state.

Kim Hak Song, an evangelical Christian missionary, worked for the Pyongyang University of Science and Technology, the state news agency said.

If confirmed, it would make him the fourth US citizen to be held by the isolated country amid fierce diplomatic tensions with US over the North’s nuclear programme.