During the Fall of Saigon (April 26-30), the Republic of Vietnam government suffered a drastic fragmented military command in the III Corps (Saigon) except the Mekong Delta (IV Corps). President Tran Van Huong resigns on the afternoon of the 28th April and replaced by Major General Ngo Quang Truong. The PRG and North Vietnam viewed Ngo Quang Truong as untruthfulness on harmonize the unification of Vietnam and should be condemned to the show trial on the liberation. Truong urged all of ARVN forces to whatever defend itself to consolidate the frontline territories against superior NVA forces. Instead of staying in Saigon for surrender, Truong and his government aides evacuated by air to relocate new capital Cần Thơ (IV Corps) where his mightily almost 150,000 ARVN soldiers wanting to fight for the democracy and tenacity of the new republic one day.
After the communists took over Saigon, the IV Corps still remained high intensify combat even though the American halts most of the military supplies to South Vietnam. The U.S cuts off the relationship with South Vietnam's new capital Cần Thơ because they knew the communists from the outskirts unleashes the final blow to occupy relocate capital Cần Thơ. However, the PRG and North Vietnamese calls for his troops to halt the further offensive campaign due to the pressured by the China and France threatening to reduce the diplomatic talks and possibly putting some sanctions. French diplomat to NVN replies, "This is an opportunistic friendly lessons. I will simply withdraw the invest supports if you don't protect the foreigners in Delta." In June 1975, the U.S re-established relationship with newly South Vietnam at Can Tho.