<P> In 2010, the sinking of a South Korean naval ship, the Cheonan, allegedly by a North Korean torpedo, and North Korea's shelling of Yeonpyeong Island escalated tensions between North and South . </P> <P> Kim Jong - il died on December 17, 2011 and was quickly succeeded by his son, Kim Jong - un . In late 2013, Kim Jong Un's uncle Jang Song - thaek was arrested and executed after a trial . According to the South Korean spy agency, Kim may have purged some 300 people after taking power . In 2014, the United Nations Commission of Inquiry accused the government of crimes against humanity . </P> <P> In 2015, North Korea adopted Pyongyang Standard Time (UTC + 08.30), reversing the change to Japan Standard Time (UTC + 9.00) which had been imposed by the Japanese Empire when it annexed Korea . As a result, North Korea was in a different time zone than South Korea . In 2016, 7th Congress of the Workers' Party of Korea was held in Pyongyang, the first party congress since 1980 . </P> <P> In 2017, North Korea tested the Hwasong - 15, an intercontinental ballistic missile capable of striking anywhere in the United States of America . Estimates of North Korea's nuclear arsenal at that time ranged between 15 and 60 bombs, probably including hydrogen bombs . </P>

Who ruled north korea during the korean war