Question: when were the last troops deployed to vietnam

title: Vietnam War
text: On 20 March , Thieu reversed himself and ordered Huế , Vietnam 's third - largest city , be held at all costs , and then changed his policy several times . Thieu 's contradictory orders confused and demoralized his officer corps . As the North Vietnamese launched their attack , panic set in , and ARVN resistance withered . On 22 March , the NVA opened the siege of Huế . Civilians flooded the airport and the docks hoping for any mode of escape . Some even swam out to sea to reach boats and barges anchored offshore . In the confusion , routed ARVN soldiers fired on civilians to make way for their retreat .