South Vietnamese Government troops have been battling against a two-pronged Communist advance in Tay Nihn district, some 40 miles (64 kms) north of Saigon, during the weekend (March 15-16).

Communist forces using tanks were reported moving into the district both from the Khmer border, to the west, and from a district town to the east which was overrun last week.

As the fighting intensified, Government war planes attacked communist positions. A fighter bomber and a light observation plane were both shot down during operations near the town of Hieu Thien, thought to be a possible target for the Communist pincer movement.

The town lies on Highway 22, linking Saigon with the provincial capital Tay Nihn, which the Communists cut several days earlier.

Government armoured units were reported moving up the highway from Saigon to join the battle and prevent any communist attempt to cut Tay Ninh off permanently.

Over the weekend, the government troops succeeded in reopening the highway. But at the same time, at least six government outposts in the providence were being overrun by tank-led communist forces.