The Republic of Korea Navy was established as the Marine Defense Group on November 11, 1945 after Korea was liberated from the Empire of Japan on August 15, 1945. Since the Korean War, the South Korean navy had concentrated its efforts on building naval forces to counteract hostilities of North Korea. As South Korea's economy grew, the ROK Navy was able to locally build larger and better equipped fleets to deter aggression, to protect the sea lines of communication, and to support the nation's foreign policy. As part of its mission, the ROK Navy has engaged in several peacekeeping operations since the turn of the 21st century. The ROK Navy aims to become a blue-water navy in the 2020s.