Tung had been trained by the CIA in the United States. A Diệm loyalist, he led a force of 1,840 men, which operated under the direction of Nhu rather than the army command. He did not conduct operations against the communist Việt Cộng insurgents, but used his forces mainly in Saigon to repress opponents of the Diệm regime. Tung's most notable attacks occurred during the Buddhist crisis of 1963. During this period, the Buddhist majority engaged in mass protests against the pro-Catholic policies of the Diệm regime.