In 1960, the Assam Provincial Congress Committee(APCC) met on 22 April 1960, and directed the Chief Minister Chaliha to declare the Assamese as the State language. This further infuriated the tribal people, but accelerated the movement for Hills state, and subsequently in a All Assam Hills leaders conference held at Tura, Garo Hills, on 28 April 1960, they vehemently opposed the imposition of Assamese language and demanded the immediate amendment of the Sixth Schedule. With outbreak of violence between the Assamese speaking and Bengali speaking communities in the Assam plains, it further united the Hill parties and Hill state movement gained its momentum once again. In June 1960, W.A. Sangma called for a conference of all leaders of all the political parties in the hill areas. The conference unanimously resolved to oppose the Official Language Bill. It also resolved to form the All Party Hill Leaders Conference(APHLC), with W.A. Sangma as its first chairman. In September 1960, the APHLC's Council of Action issued an ultimatum to the Assam CM; consequently, W.A. Sangma resigned his cabinet post from the government in protest against the official Assamese language policy adopted by the Assam government.