The 2006 North Korean nuclear test was the detonation of a nuclear device conducted by North Korea on October 9, 2006. North Korea announced its intention to conduct a test on October 3, six days prior, and in doing so became the first nation to give warning of its first nuclear test. The blast is 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.