In May 1963 , in the central city of Huế , where Diệm 's elder brother Ngô Đình Thục was the archbishop , Buddhists were prohibited from displaying Buddhist flags during Vesak celebrations yet few days earlier , Catholics were allowed to fly religious flags at a celebration in honour of the newly seated archbishop . This led to widespread protest against the government ; troops were sent in and nine civilians were killed in the confrontations . This led to mass rallies against Diệm 's government , termed as the Buddhist crisis . The conflicts culminated in Thích Quảng Đức 's self-immolation . President Diệm 's younger brother Ngô Đình Nhu favored strong-armed tactics and Army of the Republic of Vietnam Special Forces engaged in the Xá Lợi Pagoda raids , killing estimated hundreds . Dismayed by the public outrage , the US government withdrew support for the regime . President Diệm was deposed and killed in the 1963 coup
Xá Lợi Pagoda raids
Xá Lợi Pagoda raids
Buddhism in Vietnam