Relations between China and Vietnam deteriorated, partly because of the repression of the Hoa. Although vast majority of the "Boat People" were ethnic Vietnamese (see below), those who sailed for refuge to China were largely Hoa people. In February 1979, following Vietnam's occupation of Cambodia, China launched an offensive against Vietnam, briefly occupied parts of its north and then withdrew from Vietnam. This is called the Sino-Vietnamese War. The Vietnamese government initiated a policy of encouraging the Hoa to leave the country and charging them a fee of several thousand dollars to do so. Because of the outflow, the Hoa population of Vietnam declined during the 1980s.