<Li> 1949--Chinese communists reach the northern border of Indochina . The Viet Minh drive the French from the border region and begin to receive large amounts of weapons from the Soviet Union and China . The weapons transform the Viet Minh from an irregular large - scale insurgency into a conventional army . </Li> <Li> May 1, 1950--After the capture of Hainan Island from Chinese Nationalist forces by the Chinese People's Liberation Army, President Truman approves $10 million in military assistance for anti-communist efforts in Indochina . The Defense Attaché Office was established in Saigon in May 1950, a formal recognition of Viet Nam (vice French IndoChina). This was the beginning of formal U.S. military personnel assignments in Viet Nam . U.S. Naval, Army and Air Force personnel established their respective attaches at this time . </Li> <Li> September 1950--Truman sends the Military Assistance Advisory Group (MAAG) Indochina to Vietnam to assist the French . The President claimed they were not sent as combat troops, but to supervise the use of $10 million worth of U.S. military equipment to support the French in their effort to fight the Viet Minh forces . </Li> <Li> Following the outbreak of the Korean War, Truman announces "acceleration in the furnishing of military assistance to the forces of France and the Associated States in Indochina ...". and sends 123 non-combat troops to help with supplies to fight against the communist Viet Minh . </Li>

When did the us officially enter the vietnam war