battalions were located in the province, supported by six 105-mm. howitzer platoons (12 guns), which had had no occasion to fire since the 28 January ceasefire. Additionally, 27 Popular Force platoons were scattered about the province. These were nearly all Montagnards, and the province population was 60 percent tribal. Around the beginning of May, a Regional Force patrol, moving out from its outpost near Bu Prang made contact with a PAVN reconnaissance party and killed four. The rest of May and June were quiet until PAVN harassment of the RF positions around Bu Prang began in early July, evidently in response to the unusually aggressive patrolling ordered by Col. Nguyen Hau Thien, Quang Duc's province chief. Mortar attacks, accompanied by some light infantry probes, continued through July, as did RF forays into the old Bu Prang positions on the border west of the Tuy Đức crossroads. In the last week of August, Col. Thien tried a reconnaissance in force with two RF battalions. Both met heavy resistance short of their objectives on the border and returned to camp. This inconclusive skirmishing took on an ominous note in early September when the first evidence appeared disclosing that COSVN had sent two battalions of its 271st Independent Regiment from southwest of Tây Ninh up to Quang Duc. The presence of a PAVN main force regiment was a new and dangerous development in Quang Duc. Colonel Thien asked for reinforcement and was given an RF battalion from Darlac Province. He complained about the poor performance of the Darlac battalion, and II Corps commander General Nguyễn Văn Toàn agreed to replace it with another battalion from Khanh Hoa Province. This gave Colonel Thien a force of four RF battalions, which he located at the mutually supporting bases of Bu Prang and Bu Bong (), each with a platoon of 105-mm, howitzers. The 271st Independent Regiment had been roughly handled by the ARVN and Republic of Vietnam Air Force (RVNAF) in the early months of 1973 in marsh and ricelands along the Vàm Cỏ Đông River and the Cambodian border in Hậu Nghĩa and southern Tây Ninh Provinces. COSVN had pulled it back to Cambodia in April for reorganization and recuperation. Afterwards the regimental headquarters and two of its battalions, the 8th and 9th, were trucked to Bù Đốp Camp in northern Phước Long Province, while the other, the 7th, was sent to operate under