11th Airborne Battalion then deployed by helicopters to recapture Du Long town () and the Du Long Pass (), meanwhile the 5th Airborne Battalion secured the area around Phan Rang AB and cleared Route 11. On 10 April the PAVN 10th Division left Cam Ranh and moved along Route 450 to join up with Route 11 to take Dalat, passing within of Phan Rang AB. When RVNAF reconnaissance aircraft observed the movement of the 10th Division, Phan Rang based A-37s began attacking the column, destroying 6 river-crossing vehicles on 10 April, 5 trucks on 11 April, 7 trucks on 12 April and 9 trucks on 13 April. On 11 April the 5th Airborne Battalion was withdrawn to Saigon and on 12 April the rest of the 2nd Airborne Brigade was ordered to withdraw to Saigon. On 13 April the 31st Rangers arrived by air from Bien Hoa while the ARVN 4th and 5th Regiments, 2nd Division arrived by road from Phan Thiết to replace the Airborne. The 31st Rangers deployed to Du Long to replace the 11th Airborne Battalion on the evening of 13 April. The PAVN meanwhile had decided to eliminate Phan Rang and at 05:30 on 14 April the PAVN 3rd Division began an artillery attack on the 31st Rangers at Du Long Pass and the 3rd Airborne at Bà Râu. At 06:30 PAVN tanks and infantry attacked to 31st Rangers' position but were forced back. At 07:00 2 A-37s accidentally bombed the Rangers. The PAVN then bypassed the Rangers and attacked Du Long Town quickly defeating the Regional Forces there and outflanking the 31st Rangers at the pass. Reinforcements from the 52nd Rangers were sent to support the 31st Rangers, but they were unable to break through and at 16:00 the 31st Rangers were ordered to withdraw with only 80 Rangers successfully returning to Phan Rang AB. At the same time as the attack on Du Long, the PAVN 25th Regiment infiltrated to attack Phan Rang AB. Despite helicopter gunship fire they successfully penetrated the base and headed for the hangar area where they were met by the 11th Airborne Battalion awaiting transport back to Saigon and 4 M113 armored personnel carriers which together with air support from the helicopter gunships and A-37s forced the PAVN back outside the perimeter, killing over 100 for the loss of 6 ARVN killed and 1 M113 destroyed. At dawn on