The PAVN began their Long Khánh-Bình Tuy campaign with strong attacks against ARVN positions on the two principal lines of communication in the region, Highways 1 and 20, striking outposts, towns, bridges and culverts north and east of Xuân Lộc. On 17 March, the PAVN 209th Infantry Regiment and the 210th Artillery Regiment, 7th Division, opened what was to become the Battle of Xuân Lộc. The 209th struck first at Định Quán, north of Xuân Lộc, and at the La Nga bridge, west of Định Quán. Eight tanks supported the initial assault on Định Quán and PAVN artillery fire destroyed four 155 mm howitzers supporting the RF. Anticipating the attack, Đảo had reinforced the La Nga bridge the day before, but the intense fire forced a withdrawal from the bridge. After repeated assaults, the 209th Infantry penetrated Định Quán and the 2nd Battalion, 43rd Infantry, as well as the RF battalion were forced to withdraw with heavy losses on 18 March.