[2][3]: 93 Under orders to maintain a loose siege of Đức Huệ, the PAVN, assisted by the local sapper battalion, blocked the only land access to the camp and continued the artillery bombardment but abandoned the idea of taking it by storm.
Fighting raged in the paddies east and north of the camp for several days, and the Republic of Vietnam Air Force (RVNAF) provided effective support to the counterattacking infantry, losing an A-1 Skyraider and an observation aircraft to SA-7 antiaircraft missiles.
Lieutenant general Phạm Quốc Thuần, III Corps commander, determined that he must reduce the threat to his western flank and the Tây Ninh corridor while he had the opportunity to do so before the onset of the southwest monsoon.
The details and timing of the operation were carefully safeguarded, and few, if any, Americans in the Defense Attaché Office, Saigon knew anything about it until 27 April when 45 RVNAF sorties struck targets in Cambodia and known and suspected bases of the PAVN 5th Division.
These strikes began Phase I, which lasted through the 28th and included infantry sweeps by two Regional Force (RF) battalions between the Vàm Cỏ Đông River and the northern shoulder of the Angel's Wing.
Another supporting maneuver, which quickly developed into a major operation, was the attack into Svay Rieng Province south of the Elephant's Foot (10°52′N 105°54′E / 10.87°N 105.9°E / 10.87; 105.9) by two battalions from IV Corps.
The other battalion crossed midway between the Elephant's Foot and the tip of the Parrot's Beak and established a lodgment on the southeastern edge of the PAVN logistical base and assembly area in Svay Rieng.
Not only were the Long Khốt defenders tenacious and prepared for the onslaught, but the RVNAF proved its worth in close support as over the two days, the 27th and 28th, it flew 188 tactical and logistical sorties in the Svay Rieng Campaign.
Combat pilots returned to their bases with morale-building reports about PAVN troops throwing down their weapons and running when faced with low-level strafing.
[3]: 93–4 [1] By the night of 28 April, 11 ARVN battalions of infantry, RF, and Rangers were conducting screening, blocking, and reconnaissance-in-force operations as a prelude to Phase II of the Svay Rieng sweep.
As the threat to the 5th Division base in southern Svay Rieng became critical the PAVN was compelled to reduce the pressure on Long Khốt and concentrate on attempting to relieve the E-6 and 174th Regiments and logistical installations lying in the path of the ARVN armored thrusts.
On the other hand, the speed, audacity and superior air-ground coordination that characterized the attack had kept South Vietnamese casualties extremely low: only 21 killed and 64 wounded.
The ARVN 7th Division had moved a forward command post into Mộc Hóa and was controlling the operation of two task forces then committed in the Elephant's Foot.
Meanwhile, Task Force 322 was committed and advanced about 4km into the center of the Angel's Wing, and the infantry battalions of the 25th Division continued their sweep between Đức Huệ and Go Dau Ha.
The tank-heavy 322nd Task Force turned south and headed for Ba Thu (10°53′42″N 106°07′55″E / 10.895°N 106.132°E / 10.895; 106.132), the long-held PAVN base on the border southwest of Đức Huệ.