 They advanced along parallel tracks, with the 5/7th Cavalry, following the course of Highway 1; the 2/501st Infantry, searching the central route; and the 2/12th Cavalry, sweeping the area to the south.In mid-morning the 5/7th Cavalry, came under heavy fire from an estimated company-size force who occupied the hamlet of Thon An, approximately one kilometer from the An Hoa Bridge.Helicopter gunships and artillery and the pair of Dusters systematically leveled any structure that appeared to serve as a strong point.