sentences:  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.