The smoke appears to be from explosions set off by overhead bombing of ammunition or petroleum products. The Cambodian border is a few miles from the location of the attack and the North Vietnamese Army had supplies stashed many places in the jungle near the border. Various infantry and mechanized units of the 25th Division were assigned to find and destroy them. We were told NVA units were garrisoned there with a mini Pentagon which commanded their operations in our part of Vietnam. The American invasion of Cambodia was launched from this area and involved many battalions of the 25th Division.