The plan which Giap developed for the General Offensive was breathtaking in its audacity. It entailed simultaneous attacks in virtually every city, provincial capital and town of consequence in South Vietnam. Spearheaded by Viet Cong assault troops, the initial attacks would be aimed at garrisons, police headquarters, command posts and radio stations. These initial assaults were expected to trigger the National Uprising, which would be announced in radio broadcasts across the country, for which reason South Vietnamese national radio in Saigon was a critical target. A follow-up wave of North Vietnamese regulars would consolidate the gains and take advantage of the confusion generated by the outbreak of the National Uprising to complete the overthrow of the Americans and the hated puppet regime. To divert American attention-and perhaps gain a major victory - Giap ordered three divisions to move south and lay siege to the isolated Marine base at Khe Sanh in the extreme northwestern corner of the country.
It took time for the assault teams to infiltrate the cities and towns and only the Viet Cong could be used since the PAVN regulars' northern accents would give them away. American and South Vietnamese intelligence learned of an offensive in the making a week or so in advance, but badly underestimated its strength. General Westmoreland cancelled several deployments of U.S. troops and held them in their base areas as a precaution. General Frederick Wey and, commanding Army forces in the Saigon area, put his troops on full alert. In the end, the communists compromised surprise with a series of premature attacks in towns across the center of the country on the night of 29-30 January. It was now clear that a major attack would come the following night. Westmoreland put all American units on full alert and President Thieu ordered all ARVN soldiers on leave for Tet to return to their units. Even so, when the blow came it was stunning in its power. Across the country, ARVN troops and security forces fought for their lives ahd U.S. bases were heavily bombarded with rockets and shells.
The communists quickly overran much of Hue and there was chaos in Saigon: a Viet Cong assault group broke into the American Embassy. Another captured the National Radio Station; they carried tapes announcing the National Uprising, but were frustrated by the foresight of an ARVN commander who had arranged for power to the transmitters to be cut remotely. The next day saw scenes of devastation and destruction. In America, citizens who only weeks earlier had been assured that the end was in sight tuned in to the television news to see footage of flaming buildings in Saigon and of Viet Cong and American bodies lying side by side in the embassy courtyard. A television appearance by an obviously shaken Lyndon Johnson did nothing to restore confidence.