By April, the weakened South Vietnamese Army had collapsed on all fronts. The powerful NVA offensive forced South Vietnamese troops on a bloody retreat that ended up as a hopeless siege at Xuan-loc, a city 40 miles from Saigon, and the last South Vietnamese defense line before Saigon. On April 21st, the defense of Xuan-loc collapsed and NVA troops and tanks rapidly advanced to Saigon. On April 27th, 100,000 NVA troops encircled Saigon which was to be defended by 30,000 ARVN troops. On April 29th, the US launched Option IV, the largest helicopter evacuation in history. Chaos, unrest, and panic ensured as hectic Vietnamese scrambled to leave Saigon before it was too late. Helicopters began evacuating from the US embassy and the airport. Evacuations were held to the last minute because US Ambassador Martin thought Saigon could be held and defended. The operation began in an atmosphere of desperation as hysterical mobs of South Vietnamese raced to takeoff spots designated for evacuation, many yelling to be saved. Martin had pleaded to the US government to send $700 million dollars in emergency to South Vietnam in order to bolster the Saigon regimes ability to fight and to mobilize fresh South Vietnamese units. But the plea was rejected. Many Americans felt the Saigon regime would meet certain collapse. President Ford gave a speech on April 23, declaring the end of the Vietnam War and the end of all American aid to the Saigon regime. The helicopter evacuation continued all day and night while NVA tanks reached the outskirts of Saigon. In the early hours of April 30th, the last US Marines left the embassy as hectic Vietnamese breached the embassy perimeter and raided the place. NVA T-54 tanks moved into Saigon. The South Vietnamese resistance was light. Tank skirmishes began as ARVN M-41 tanks attacked the heavily armored Soviet T-34 tanks. NVA troops soon dashed to capture the US embassy, the government army garrison, the police headquarters, radio station, presidential palace, and other vital targets. The NVA encountered greater-than expected resistance as small pockets of ARVN resistance continued. By now, the helicopter evacuations that had saved 7,000 American and Vietnamese had ended. The presidential palace was captured and the Vietcong flag waved victoriously over it. President Minh surrendered Saigon to the NVA colonel Bui Tin. The surrender came over the radio as Minh ordered South Vietnamese forces to lay down their weapons. Columns of South Vietnamese troops came out of defensive positions and surrendered. Saigon fell on April 30th, 1975. As for the Americans, many stayed in South Vietnam but by May 1st, 1975 most Americans had fled, leaving the city of Saigon forever. The Vietnam War was America’s most humiliating defeat, with over 58,000 dead and many left severely injured. As for the people of South Vietnam, over a million ARVN soldiers died in the 30-year conflict.