South Vietnamese airborne troops have in the last days rescued about 1,000 South Vietnamese and United States troops who had survived a fortnight of constant shelling and infantry attacks on a lonely artillery outpost in the Central Highlands of South Vietnam.

Firebase Six stands on a hilltop only six miles (10 kms.) from the border junction of South Vietnam, Laos and Cambodia, and commands a key infiltration route into the Central Highlands area. It guards the road to the nearby town of Ben Het, which suffered a six-week siege in 1969.

Although the operation to break the siege was launched with U.S. artillery support and was preceded by heavy B-52 aerial bombardment, it was largely an ARVN action. The troops sent in to relieve the base were South Vietnamese and 40 per cent of the helicopter pilots were South Vietnamese -- the highest proportion in any major action so far.

Earlier reports estimated the number of North Vietnamese in the area at up to 10,000, but casualties inflicted in the assault were light and it appears the North Vietnamese largely withdrew into Cambodia to regroup.

Visnews cameraman Tran Huu Trong went in with the airborne troops to bring back this dramatic film of the battle, and recorded his own sound.

SYNOPSIS: Under cover of United States artillery, and preceded by B-52 bombers, the South Vietnamese army has just completed one of its most successful airborne operations to date, the relief of 1,000 South Vietnamese troops and about 30 US personnel who'd been under siege for a fortnight on a lonely hill-top in the Central Highlands. The troops who broke the siege were South Vietnamese, and so were 40 per cent of the helicopter pilots, the highest proportion in any major action to date.

Firebase Six commands a vital infiltration route and stands only six miles (10 km.) from the borders of Laos and Cambodia. It was overrun by North Vietnamese troops on March 31st, but recaptured by the South next day. That was when the siege began. Attempts by South Vietnamese ground troops to relieve the beleaguered garrison had failed, so the decision was taken to mount a full airborne assault.

The first relief troops -- two elite airborne battalions -- were dropped about a mile (2 km) south of the base and fought their way through jungle to reach the battered perimeter. The troops they had come to rescue were hungry and exhausted, having bene pinned down in their foxholes by continuous artillery and small-arms fire. They had little ammunition left.

The garrison troops had been subjected to at least four waves of attack on all sides from a North Vietnamese force estimated at up to ten thousand men. The first exploded the mines on the perimeter, the second used up all their hand grenades, and the third and fourth almost exhausted the supply of bullets. But by the time the main force of relief troops was airlifted in, the helicopters were meeting only sniper fire, and the action inflicted relatively light casualties. It appeared the main body of North Vietnamese had withdrawn into Cambodia to regroup.

Meanwhile, intelligence reports said an even larger force was on its way to Southern Laos. It seems the Hanoi spring offensive in the Central Highlands is not over yet.