15 April the PAVN shelled the 3rd Airborne Battalion at Bà Râu and Kien Kien () on Route 1 and then attacked their position. Although outnumbered, the Airborne held back the assault until midday when it blew the highway bridge and then withdrew onto Ca Dau mountain to the east. At 02:00 on 16 April an RVNAF EC-47 intercepted a PAVN radio transmission indicating an armored attack on Phan Rang would start at 05:00. A-37 aircraft were launched to attack PAVN positions along Route 1 and at 03:00 reconnaissance reported a large PAVN force moving through the Du Long Pass. Meanwhile, VC forces began attacking the base perimeter and on Ca Dau Mountain. At 05:00 the PAVN artillery bombardment commenced and this was soon followed by an armored spearhead of 20 tanks and armored personnel carriers of the 4th Battalion, 203rd Tank Brigade supported by truck mounted infantry of the 101st Regiment and anti-aircraft guns. While the lead tank was destroyed by an ARVN rocket, the PAVN force quickly cut through the 3rd Airborne platoon holding Kien Kien. The RVNAF at the base mounted numerous airstrikes on the armored column destroying vehicles, taking losses from the antiaircraft fire and by 08:00 the armored vehicles were on the outskirts of the city. However the truck-mounted infantry had dispersed to avoid the airstrikes and the anti-aircraft vehicles had not kept up with the advance, leaving the 101st Regiment vulnerable to further air attacks which destroyed or damaged another 16 vehicles and killing numerous PAVN soldiers. The PAVN 3rd Division then attacked the Airborne troops on Ca Dau Mountain and allowed the 101st Regiment to resume its advance. After overcoming a Regional Force roadblock on the outskirts of the city for the loss of 2 tanks and many infantry, the PAVN pushed into the city capturing the Provincial Headquarters. By 09:30 the PAVN had captured the port and a bridge on Route 1 south of the city sealing off all sea and land escape routes. At 08:45 a battalion-sized PAVN mechanized force attacked along Route 11 towards the base. While one element attacked the 5th Regiment defending Route 11, the other moved around it to attack the base directly and at the same time the 25th Regiment attacked the north of the base. The 5th Regiment soon broke and ran allowing the PAVN to attack the base's main gate, while the 25th Regiment