 Complete the following phrase:  In May 1963, in the central city of Huế, where Diệms 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 Diệms government, termed as the Buddhist crisis. The conflicts culminated in Thích Quảng Đứcs self-immolation by lighting himself on fire in protest of the persecution of Buddhists. President Diệms 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 U.S. government withdrew support for the regime. President Diệm was 