 The ARVN, based at the administrative centre of Phước Bình and Phước Long, suddenly found themselves surrounded by the PAVN 4th Army Corps.To halt the North Vietnamese onslaught at Phước Long, Lieutenant General Dư Quốc Đống need at least one infantry division and one unit of armoured cavalry, however ARVN infantry divisions based in III Corps were not allowed to be deployed without the approval of President Thiệu.On December 29, realising that the district of Phước Long was in serious danger of being overrun, General Cao Văn Viên asked President Thiệu to approve a plan to defend Phước Long that had been prepared back in October 1974.