a key South Vietnamese relief force defending the embattled town of An Loc, 60 miles north of Saigon, broke into a wild four-mile retreat under furious enemy rocket fire yesterday, a Vietnamese officer caught in the battle said.

The panic was so great that during the retreat some drivers of armoured personnel carriers ran over government soldiers accompanying them, the unofficial report stated. The column, now about 11 miles south of An Loc, had been under siege for three days.

Enemy tanks captured the northern section of the town Thursday, but An Loc's defenders reported they drove the Vietcong from all but two blocks of the provincial capital last night. President Nguyen Van Thieu ordered the remaining 12,000 man government force to hold the town at all costs.

As the fighting intensified around An Loc, the North Vietnamese fired a series of five artillery rockets into a Saigon suburb, attacking he capital for the first time since the Communist offensive began 16 days ago. An air base and some civilian housing were bombed, killing 15 persons and wounding 6, police officials said.