South Vietnam. In a scathing attack, he suggested that Kissinger had tricked him into signing the Paris peace agreement two years earlier, promising military aid that failed to materialize. Having transferred power to Trần Văn Hương on 21 April, he left for Taiwan on 25 April. After having appealed unsuccessfully to Congress for $722 million in emergency aid for South Vietnam, President Ford had given a televised speech on 23 April, declaring an end to the Vietnam War and all U.S. aid. By the end of April, the ARVN had collapsed on all fronts except in the Mekong Delta. Thousands of refugees streamed southward, ahead of the main communist onslaught. On 27 April, 100,000 PAVN troops encircled Saigon. The city was defended by about 30,000 ARVN troops. To hasten a collapse and foment panic, the PAVN shelled Tan Son Nhut Airport and forced its closure. With the air exit closed, large numbers of civilians found that they had no way out. Fall of Saigon Chaos, unrest, and panic broke out as hysterical South Vietnamese officials and civilians scrambled to leave Saigon. Martial law was declared. American helicopters began evacuating South Vietnamese, U.S. and foreign nationals from various parts of the city and from the U.S. embassy compound. Operation Frequent Wind had been delayed until the last possible moment, because of U.S. Ambassador Graham Martin's belief that Saigon could be held and that a political settlement could be reached. Frequent Wind was the largest helicopter evacuation in history. It began on 29 April, in an atmosphere of desperation, as hysterical crowds of Vietnamese vied for limited space. Frequent Wind continued around the clock, as PAVN tanks breached defenses near Saigon. In the early morning hours of 30 April, the last U.S. Marines evacuated the embassy by helicopter, as civilians swamped the perimeter and poured into the grounds. On 30 April 1975, PAVN troops entered the city of Saigon and quickly overcame all resistance, capturing key buildings and installations. Two tanks from the 203rd Tank Brigade of the 2nd Corps crashed through the gates of the Independence Palace and the Viet Cong flag was raised above it at 11:30 am local time. President Dương Văn Minh, who had succeeded Huong two days earlier, surrendered to Lieutenant colonel Bùi Văn Tùng, the political commissar of the 203rd Tank Brigade. Minh was then escorted to Radio Saigon to announce the surrender declaration (spontaneously written