On 28 April the commander of the 20th Tank Battalion withdrew from Đông Hà to deal with a PAVN force threatening Ái Tử, seeing the tanks leaving the soldiers of the 57th Regiment panicked and abandoned their positions leading to the collapse of the ARVN defensive line.[1]: 78 The VNMC 7th Battalion was sent to Ái Tử to help defend the base.[4]: 78 At 02:00 on 29 April the PAVN attacked the ARVN positions north and south of the base and the ARVN defenses began to crumble, by midday on 30 April General Giai ordered a withdrawal from Ái Tử to a defensive line along the south of the Thạch Hãn River and the withdrawal was completed late that day.[4]: 79–80 On 1 May with his forces disintegrating General Giai decided that any further defense of Quảng Trị city was pointless and that the ARVN should withdraw to a defensive line along the Mỹ Chánh River 13 km to the south, he made this decision with the tacit approval of I Corps commander General Hoàng Xuân Lãm.[4]: 82–3 [2]: 44 The 147th Marine Brigade which was the only unit maintaining any cohesiveness departed the city in an armored convoy, while the 3rd Division command group was evacuated by US helicopters after attempting to leave the city by road.[2]: 45 By 2 May all of Quảng Trị Province had fallen to the PAVN and they were threatening Huế.[4]: 90 By the late evening of 2 May General Giai was attempting to reorganize the remnants of the 3rd Division at Camp Evans.[2]: 46–7