Regiment 174 utilised its reserve forces and was no longer able to handle A1; while Regiment 98’s unsuccessful attack on C2 left its forces depleted. This required further units to be sent to fight against the enemy on Hill A1 and defend the C1 high-point during the day.
At the same time, the Campaign Command instructed military units to urgently organise defensive battlefields on highpoints C1, D1, E, prepare to counterattack against the enemy during the day, determined not to let the enemy recapture these highpoints.
On the enemy side, in the early morning of March 31, 1954, the French Command in Dien Bien Phu held a meeting to discuss the current situation. At 7:45 AM the same day, French Battalion 3, and a tank from Hong Cum heading to Road 41 toward Muong Thanh, was surrounded by Vietnam’s Regiment 57 in Long Nhai Village.
The tank was hit by DKZ bullets and caught fire, while the troops were destroyed by Vietnam’s heavy fire. At noon, the enemy’s artillery had to fire to make a way out for the Battalion 3 and the tank to back to Hong Cum, with 15 corpses and 50 wounded soldiers.
The weather was good, the enemy's air force was back in action, C-119 transport aircrafts controlled by American pilots parachuted in supplies of ammunition and food. Fighter planes also swooped down, working together with French artillery to bombard high points C1, D1, E, and A1.
During the day, the Vietnamese soldiers of all units fought bravely and tenaciously, repelling many enemy counterattacks, recapturing lost targets at hills D1 and C1, and organising the second attack against the enemy at Hill A1.
Reinforced by a company of Regiment 174, Regiment 102 organised an attack against the enemy at Hill A1. However, despite organising four waves of attack, Vietnamese soldiers failed to conquer the enemy in front of the underground tunnel.
The battle took place fiercely, the enemy occupied two third of the base, and Vietnam took control remaining one third part on the eastern side of Hill A1.
Meanwhile, in the Inter-Region 4, Vietnamese troops overturned a train and destroyed a company of the enemy.
