After six months of tension and growing opposition to the regime, leaders of the army, supported by the CIA, conducted a coup on 1 November 1963, including the arrest and assassination of Ngô Đình Diệm the following day.

Specifically, the government was regarded as being biased towards Catholics in public service and military promotions, as well as the allocation of land, business favors and tax concessions.

[9] Additionally, the distribution of firearms to village self-defense militias intended to repel Việt Cộng guerrillas saw weapons only given to Catholics, with Buddhists in the army being denied promotion if they refused to convert to Catholicism.

[10] Some Catholic priests ran their own private armies,[11] and in some areas forced conversions, looting, shelling and demolition of pagodas occurred.

[12] Some Buddhist villages converted en masse in order to receive aid or to avoid forcible resettlement by Diệm's regime.

[13] The Catholic Church was the largest landowner in the country, and the "private" status that was imposed on Buddhism by the French, which required official permission to conduct public Buddhist activities, was not repealed by Diệm.

The application of the law caused indignation among Buddhists on the eve of the most important religious festival of the year, since a week earlier Catholics had been allowed to display Vatican flags to celebrate the 25th anniversary of the appointment of Diệm's brother, Thục, as Archbishop of Huế.

[19] In spite of this, the authorities in Hue tore down thousands of Buddhist flags that had already been unfurled on homes and pagodas in preparation for Phật Đản.

Villages in the central region had converted en masse to Catholicism, with priests allowed special access to government facilities and funds.

More than 500 people marched across the Perfume River, carrying signs and placards, congregating at the Từ Đàm Pagoda before a 3,000-strong demonstration, calling for religious equality, took place in the city centre as government security officials surrounded the area with armoured personnel carriers and civil guardsmen.

[22] The leading Buddhist activist monk Thích Trí Quang addressed the crowd and exhorted them to rise up against Catholic discrimination against Buddhism.

Another theory at the time was that a CIA agent had caused the blasts with the aim of fomenting sectarian tension and destabilising the Diệm regime.

He claimed all parties were responsible, the demonstrators for (as he alleged) trying to take over the radio station, the government for deploying the army, which later opened fire, and "agitators" for throwing the explosives.

A government-organised counter-demonstration to condemn the "Việtcộng terrorist act" under the leadership of Diệm's brother, Ngô Đình Nhu, attracted almost nobody.

Thích Trí Quang, who had traveled throughout the country protesting against religious inequality and the flag ban, began rallying Buddhists in central Vietnam.

Such an emotion-charged spectacle would likely have attracted thousands of spectators and placed pressure on Diệm's regime to grant reforms, so the government announced a curfew and put all armed personnel on duty around the clock to "prevent VC infiltration".

[31] After the fall of the Diệm regime in a coup on 1 November 1963, Đặng Sỹ faced a trial held under a government led by Nguyễn Khánh.

Some of the accusations were that Sỹ's men had fired on the crowd and crushed the victims with armored cars, or that the grenades had been launched at his orders and caused the deaths.

In 1970, the Saigon-based Catholic newspaper Hòa Bình ran a story claiming that CIA agents had used a secret new explosive to foment trouble for Diệm's regime, whose relations with the United States were deteriorating.