In January 2002 U.S. President George W. Bush , in his first State of the Union Address , labeled North Korea a part of an Axis of Evil . In October 2006 North Korea conducted its first nuclear weapons test . There were two isolated violent incidents in 2010 : the ROKS Cheonan sinking , which was attributed to North Korea , despite denials ; and the North Korean Bombardment of Yeonpyeong . In 2010 , the U.S. position regarding a peace treaty was that it could only be negotiated when North Korea " takes irreversible steps toward denuclearization "
its first nuclear weapons test
2006 North Korean nuclear test
Korean Armistice Agreement