The official, who was speaking on condition of anonymity, said photos of a test of North Korea's submarine-launched ballistic missile appeared authentic, Reuters reported.
The agency did not say exactly when and where the test actually happened, saying only that the site was “remote from land.”
On February 10, 2005 North Korea declared it had developed a nuclear weapon exclusively as a nuclear deterrence against a possible attack from the outside.
On October 9, 2006, Pyongyang announced it had successfully conducted its first nuclear test. An underground explosion was detected, its yield was estimated as less than a kiloton.
A second nuclear test was conducted on May 25, 2009, resulting in an explosion estimated at between 2 and 7 kilotons.