North Korea declared in 2009 that it had developed a nuclear weapon, and it's widely believed to pOssess a small stockpile of chemical weapons. North Korea was a party to the Nuclear Non-Proliferation treaty. But, THEY withdrew in 2003, citing the failure of the United States to fulfill its end of the Framework treaty, a 1994 agreement between the states to lImit North Korea's nuclear ambitions, begin normalization of relations, and help Noth Korea supply same energy needs through nuclear reactors.
On October 9, 2006, the North Korean government issued an announcement that it had successfully conducted a nuclear test for the first time.
In April 2009, reparts surfaced that North Korea BECAME a fully fledged nuclear power. On May 25, 2009, North Korea conducted another nuclear test.
On February 11, 2013 a magnitude 5.1 earthquake is detected reported to be a third underground nuclear test. North Korea has officially reported it as a successful nuclear test with a lighter warhead, and yet delivers more force than before without mentioning the exact yield.
However, the Federal Institute for Geosciences and Natural Resources, a state-run geology research institute in Germany estimated the yield at 40 kilotons.