the entirety of Hainan (an island province), parts of Zhejiang (Chekiang)—specifically the Dachen Islands and Yijiangshan Islands—and portions of Tibet, Qinghai, Sinkiang and Yunnan. The Communists captured Hainan in 1950, captured the Dachen Islands and Yijiangshan Islands during the First Taiwan Strait Crisis in 1955 and defeated the ROC revolts in Northwest China in 1958. ROC forces in Yunnan province entered Burma and Thailand in the 1950s and were defeated by Communists in 1961. Ever since losing control of mainland China, the Kuomintang continued to claim sovereignty over 'all of China', which it defined to include mainland China (including Tibet), Taiwan (including Penghu), Outer Mongolia, and other minor territories. Martial law era (1949–1987) Martial law, declared on Taiwan in May 1949, continued to be in effect after the central government relocated to Taiwan. It was also used as a way to suppress the political opposition and was not repealed until 38 years later in 1987. During the White Terror, as the period is known, 140,000 people were imprisoned or executed for being perceived as anti-KMT or pro-Communist. Many citizens were arrested, tortured, imprisoned and executed for their real or perceived link to the Chinese Communist Party. Since these people were mainly from the intellectual and social elite, an entire generation of political and social leaders was decimated. Combat between both sides of the Chinese Civil War continued through the 1950s. Following the eruption of the Korean war, US President Harry S. Truman decided to intervene in the context of the Cold War and dispatched the United States Seventh Fleet into the Taiwan Strait to prevent hostilities between the ROC on Taiwan and the PRC on the mainland. The United States also passed legislations such as the Sino-American Mutual Defense Treaty and the Formosa Resolution of 1955, thereby granting substantial foreign aid to the KMT regime between 1951 and 1965. The US foreign aid fully stabilized prices in Taiwan by 1952. The KMT government instituted many laws and land reforms that it had never effectively enacted on mainland China. Economic development was encouraged by American aid and programs such as the Joint Commission on Rural Reconstruction, which turned the agricultural sector into the basis for later growth. Under the combined stimulus of the land reform and the agricultural development programs, agricultural production increased at an average annual rate of 4 percent from 1952 to 1959, which was greater than the population