Mao Zedong decided to begin a Chinese nuclear-weapons program during the First Taiwan Strait Crisis of 1954–1955 over the Quemoy and Matsu Islands. While he did not expect to be able to match the large American nuclear arsenal, Mao believed that even a few bombs would increase China's diplomatic credibility. Construction of uranium-enrichment plants in Baotou and Lanzhou began in 1958, and a plutonium facility in Jiuquan and the Lop Nur nuclear test site by 1960. The Soviet Union provided assistance in the early Chinese program by sending advisers to help in the facilities devoted to fissile material production and, in October 1957, agreed to provide a prototype bomb, missiles, and related technology. The Chinese, who preferred to import technology and components to developing them within China, exported uranium to the Soviet Union, and the Soviets sent two R-2 missiles in 1958.