[1]: 203–4 Training for the 20th Regiment began at Ái Tử Combat Base near Quảng Trị, but proceeded slowly because of many problems, particularly in maintenance.

Repair parts and technical manuals were missing and the language barrier prevented US instructors from communicating adequately with the Vietnamese crewmen.

The regiment's final tactical test, a field training exercise, was to be conducted by the South Vietnamese Armor Command along US lines, with the proviso that any portion not completed correctly was to be repeated.

The artillery offensive was followed by infantry and armor attacks in the east across the Ben Hai River following the axis of Route 1 in the west toward the district capital of Cam Lộ and Camp Carroll.

[1]: 205–6 By early morning of 1 April most of the outlying firebases along the DMZ and in western Quảng Tri Province had been evacuated or overrun, leaving no friendly positions north of the Mieu Giang and Cua Viet rivers.

After joining a South Vietnamese Marine battalion, the tank regiment moved north from Ái Tử along Highway 1 towards Đông Hà.

Prisoners taken during this action were dismounted members of a PAVN tank unit whose mission was to seize and man South Vietnamese armored vehicles expected to be captured in the offensive.

As darkness approached, the unit set up a defensive position southeast of Cam Lo Village, withstanding PAVN probes throughout the night.

[1]: 206–7 At daybreak on 2 April, the regiment received reports that a large PAVN tank column was moving south across the Bến Hải River toward the bridge at Đông Hà.

About 09:00 the commander, Colonel Nguyen Huu Ly, received permission to move to Đông Hà, then north across the bridge to engage the PAVN forces.

When he reached the town he found PAVN infantry already occupying positions on the north bank of the Mieu Giang River that prevented his crossing the bridge.

About noon men of the 1st Squadron, from their vantage point on the high ground to the west, suddenly observed a PAVN tank and infantry column moving south along Highway 1 toward Đông Hà.

The ARVN regimental headquarters, monitoring the North Vietnamese radio net at that time, heard the PAVN commander express surprised disbelief at losing his tanks to cannon he could not see.

Toàn had urged its employment, and on the afternoon of 2 April the brigade, under 3rd Division control, assumed command of all armored, infantry, and Marine forces in the Đông Hà area.

[1]: 208 Other PAVN forces continued to move south towards Đông Hà on the afternoon of 2 April, engaged first by limited tactical air strikes and then by artillery, mortar and tank fire.

The 1st Squadron, shifted several kilometers west of Đông Hà six days earlier, occupied high ground overlooking an important road junction along Route 9.

For the next two weeks the South Vietnamese carried out clearing operations interrupted by frequent engagements with PAVN armor and infantry which normally withdrew in the late afternoon.

Through trial and error, however, the troops soon learned to engage the launch site of the AT-3 with tank main gun fire and to move their vehicles in evasive maneuvers.

[1]: 209–10 On 27 April, heralded by massive artillery attacks with 122mm rockets and 130mm guns, a new PAVN offensive began against South Vietnamese positions all along the Mieu Giang-Cua Viet River defense line.

The barrage was quickly followed by violent attacks by PAVN infantry and armor, met by equally determined resistance on the part of the South Vietnamese defenders.

Although losses were heavy on both sides, the numerically superior PAVN continued their drive, and by nightfall had pushed almost 4 km south of Đông Hà.

Forced from the highway by the PAVN, the tanks and assault vehicles moved cross-country, falling victim to the many rice paddies, canal crossings, and streams as well as the antitank rockets and artillery.

Employed primarily in a static, defensive role in frontline areas, the unit had steadily lost men and equipment without receiving replacements.

[1]: 210–2 This article incorporates public domain material from websites or documents of the United States Army Center of Military History.