1963 in the Vietnam War The Battle of Ap Bac was a small - scale battle which resulted in the first major combat victory by the Viet Cong against regular South Vietnam ese and American forces . The battle took place near the hamlet of Ap Bac , southwest of Saigon in the Mekong Delta . Forces of the 7th Division of the Army of the Republic of Vietnam ( ARVN ) , equipped with armored personnel carriers ( APCs ) and artillery and supported by American helicopters , confronted entrenched elements of the Viet Cong 261st and 514th battalions . The Hue chemical attacks was when soldiers of the Army of the Republic of Vietnam ( ARVN ) poured liquid chemicals from tear gas grenades onto the heads of praying Buddhists in Huế , South Vietnam . The Buddhists were protesting against religious discrimination by the regime of the Roman Catholic President Ngo Dinh Diem . The attacks caused 67 people to be hospitalised for blistering of the skin and respiratory ailments . Hòa thượng Thích Quảng Đức was a Vietnamese Mahayana Buddhist monk who burned himself to death at a busy Saigon road intersection on 11 June 1963 . Thích Quảng Đức was protesting against the persecution of Buddhists by South Vietnam ' s Ngô Đình Diệm administration . August . DEPTEL 243 was a high profile message sent on August 24 , 1963 by the United States Department of State to Henry Cabot Lodge , Jr . , the US ambassador to South Vietnam . The cable came in the wake of a series of bloody raids in which hundreds were believed to have been killed . The raids were orchestrated by Diem ' s brother Ngo Dinh Nhu . The message was the beginning of the end for Diem and historian John W . Newman described it as " the single most controversial cable of the Vietnam War . " The Battle of Go Cong was a small battle during the Vietnam War after the General Staff of the National Liberation Front called for " another Ap Bac " on South Vietnamese forces . Maxwell Taylor , the Chairman of the Joint Chiefs of Staff , approves a plan ( OPLAN 34A ) for covert military raids in North Vietnam . October . American troops in South Vietnam rise to 16 , 732 . In National Security Council memorandum 263 ( NSAM 263 ) John F Kennedy orders the withdrawal of 1000 American troops from South Vietnam . This policy is sometimes cited as part of a possible motive to assassinate Kennedy . ( This theory is presented in Oliver Stone ' s film " JFK " . ) The arrest and assassination of Ngo Dinh Diem , then president of South Vietnam , marked the culmination of a successful CIA - backed coup d ' état led by General Duong Van Minh . On the morning of November 2 , 1963 , Diem and his adviser , younger brother Ngo Dinh Nhu , were arrested and then killed in an armoured personnel carrier by ARVN officers . New plans for Vietnam are drawn up at a military conference in Honolulu . Defense Secretary Robert McNamara approves OPLAN 34A . President Kennedy is asassinated in Dallas . Lyndon B . Johnson becomes President of the U . S . The Battle of Hiep Hoa was a minor battle of the Vietnam War . On the night of November 22 , 1963 , an estimated 500 Viet Cong soldiers overrun the Hiep Hoa Special Forces Camp , resulting in four American personnel MIA . The Battle of Chan La was a battle of the Vietnam War . The assault by Viet Cong forces was one in a series of attacks since the battle of Ap Bac back in January . In National Security Council memorandum 273 President Lyndon B . Johnson reverses Kennedy ' s draw down and changes the goal of American involvement from supporting South Vietnam to defeating communist forces .