North Korea was a party to the Nuclear Non-Proliferation Treaty , but announced a withdrawal on January 10 , 2003 , after the United States accused it of having a secret uranium enrichment program and cut off energy assistance under the 1994 Agreed Framework . In February 2005 , North Korea claimed to possess functional nuclear weapons , though their lack of a test at the time led many experts to doubt the claim . In October 2006 , North Korea stated that , in response to growing intimidation by the United States , it would conduct a nuclear test to confirm its nuclear status . North Korea reported a successful nuclear test on October 9 , 2006 ( see 2006 North Korean nuclear test ) . Most U.S. intelligence officials believed that the test was probably only partially successful with a yield of less than a kiloton . North Korea conducted a second , higher yield test on 25 May 2009 ( see 2009 North Korean nuclear test ) and a third test with still higher yield on 12 February 2013 ( see 2013 North Korean nuclear test ) . North Korea claimed to have conducted its first hydrogen-bomb test on 5 January 2016 , though measurements of seismic disturbances indicate that the detonation was not consistent with a hydrogen bomb . On 3 September 2017 , North Korea detonated a device which caused a magnitude 6.1 tremor , consistent with a low-powered thermonuclear detonation ; NORSAR estimates the yield at 250 kilotons of TNT . In 2018 , North Korea announced a halt in nuclear weapons tests and made a conditional commitment to denuclearisation of the Korean Peninsula . Israel is widely believed to have been the sixth country in the world to develop nuclear weapons , but has not acknowledged its nuclear forces . It had " rudimentary , but deliverable , " nuclear weapons available as early as 1966 . Israel is not a party to the NPT . Israel engages in strategic ambiguity , saying it would not be the first country to " introduce " nuclear weapons into the region , but refusing to otherwise confirm or deny a nuclear weapons program or arsenal . This policy of " nuclear opacity " has been interpreted as an attempt to get the benefits of deterrence with a minimal political cost
2009 North Korean nuclear test
2009 North Korean nuclear test
List of states with nuclear weapons