On 9 October 2006, North Korea performed its first nuclear test, detonating a plutonium-based device underground.
On 3 October 2006, North Korea announced its intention to conduct a nuclear test. The blast is generally estimated to have had an explosive force of less than one kiloton, and some radioactive output was detected. United States officials suggested the device may have been a nuclear explosive that misfired.
An anonymous official at the North Korean Embassy in Beijing told a South Korean newspaper that the explosive output was smaller than expected.