 The defensive lines established on 2 April continued to hold, and on 11 April the 1st Armor Brigade was augmented by the arrival of the 18th Armored Cavalry Regiment from III Corps.By 14 April the 3rd Division controlled five regimental size South Vietnamese task forces, including units of the 4th, 11th, 17th and 18th Cavalry Regiments and the 20th Tank Regiment.On 23 April, several kilometers west of Dong Ha, the 2nd Squadron, 20th Tank Regiment was attacked by an infantry-tank force using a new weapon, the Soviet AT-3 ‘’Sagger’’ wire-guided missile, destroying an M48A3 tank and an armored cavalry assault vehicle (ACAV).