The Battle of Hainan Island occurred in 1950 during the final phase of the Chinese Civil War. The People's Republic of China (PRC) conducted an amphibious assault on the island in mid-April, assisted by the independent Hainan Communist movement, which controlled much of the island's interior, while the Republic of China (ROC) controlled the coast; their forces were concentrated in the north near Haikou and were forced to retreat south after the landings. The Communists secured the southern cities by the end of the month and declared victory on May 1.