In February, North Korea conducted an underground nuclear weapons test and confirmed with China, its only supporter in the region, that it would conduct others within the year.[24]
On March 8, 2013, the North Korean government announced that it was withdrawing from all non-aggression pacts with South Korea in response to UN Resolution 2094
[28] On March 11, 2013, the United States and South Korea began military drills amid high tensions and Pyongyang strongly condemned the exercises.[29]
On March 20, 2013, there was a cyber-attack against South Korea which added to tensions. It was later confirmed by the South Korean government that North Korea was behind the attack.[30]
On April 3, U.S. step-by-step plan "playbook" concerning high-visibility display of military power aimed at deterring North Korean provocations were released to the public.[31]
On April 4, North Korea moved what is believed to be an intermediate-range missile to its east coast, possibly in preparation for a drill or test-firing. Many nations, specifically Japan, South Korea, and the United States, viewed this move as a continuation of North Korea's attempts to provoke confrontation throughout the beginning of 2013.[32]
On April 9, North Korea issued its latest dispatch of ominous rhetoric on Tuesday, telling foreigners in South Korea they should take steps to secure shelter or evacuation to protect themselves in the event of a conflict on the Korean Peninsula. The unnerving message, announced by state-run media, followed a warning from the North the previous week to diplomats in its capital city, Pyongyang, that if war were to break out, it would not be able to guarantee their safety. In the statement, the North's Korea Asia-Pacific Peace Committee reiterated accusations that Washington and Seoul were seeking to provoke a war with Pyongyang. "Once a war is ignited on the peninsula, it will be an all-out war," the committee said, adding that North Korea doesn't want foreigners in South Korea to "fall victim" to a conflict.[33]