Besides ARVN firepower, twelve B-52 bombers from the US Air Force and naval gunfire of the United States Seventh Fleet was used to soften the PAVN-occupied Cửa Việt Base and hinder PAVN reinforcements. The PAVN put up fierce resistance to the attack, destroying 26 M-48s and M-113s with AT-3 missiles and shooting down two Republic of Vietnam Air Force planes with SA-7 missiles. At 01:45 on 28 January the Marines made a final assault and by 07:00 had broken through the PAVN lines to recapture the base. At 08:00 in accordance with the Paris Peace Accords the ceasefire came into effect and the US stopped all support for "Task Force Tango". On the evening of 29 January, the PAVN launched a counterattack against "Task Force Tango", and by the next day had succeeded in cutting off its lines of communication and began bombarding the encircled Marines. A Republic of Vietnam Navy LCM was destroyed as it tried to resupply the Marines. The Marines attempted to break out on the early morning of 31 January and the PAVN recaptured the base. South Vietnamese losses were recorded as 40 casualties and 20 armored vehicles destroyed in the battle between 28–31 January. In 1972 President Thiệu finally moved General Khang out of the Division which he had commanded since February 1964, transferring him to a nebulous "special assistant" post under General Cao Văn Viên on the Joint General Staff and replacing him with General Bui The Lan. In December 1974 the 147th Marine Brigade replaced the 2nd Airborne Brigade west of Huế. The Marine Division itself pulled two battalions out of forward positions northwest of Huế to constitute a heavier reserve and further thinning the force, sent one company from each battalion to Saigon to form the new 468th Marine Brigade for the JGS reserve effective 1 January 1975. Later in the month, Marine positions in Quảng Trị were taken over by Regional Force battalions, and three marine battalions were shifted south to Thua Thien Province. In early March the 468th Brigade was deployed to Tân An, Long An Province to stiffen the defenses of the Regional and Popular Forces there. On 9 March a PAVN assault supported by at least 20 tanks hit the Song Bo corridor defended by the 147th Brigade consisting of five battalions - the 3rd, 4th, 5th and 7th Marines and the 130th RF Battalion.