The Korean War broke out when North Korea invaded South Korea .
Cross-border skirmishes and raids at the 38th Parallel escalated into open warfare when the North Korean forces invaded South Korea on June 25 , 1950 .
The Korean War broke out when North Korean   invaded South Korea .
Cross-border skirmishes and raids at the 38th Parallel escalated into open warfare when the North Korean forces invaded South Korea on June 25 , 1950 .