In April 1975, Khmer Rouge seized power in Cambodia, and in January 1976, Democratic Kampuchea was established. During the Cambodian genocide, the CPC was the main international patron of the Khmer Rouge, supplying "more than 15,000 military advisers" and most of its external aid. It is estimated that at least 90% of the foreign aid to Khmer Rouge came from China, with 1975 alone seeing US$1 billion in interest-free economics and military aid and US$20 million gift, which was "the biggest aid ever given to any one country by China". In June 1975, Pol Pot and other officials of Khmer Rouge met with Mao Zedong in Beijing, receiving Mao's approval and advice; in addition, Mao also taught Pot his "Theory of Continuing Revolution under the Dictatorship of the Proletariat（无产阶级专政下继续革命理论）". High-ranking CPC officials such as Zhang Chunqiao later visited Cambodia to offer help.