On February 5, based on intelligence of the enemy's continued buildup and the positioning of his major troop units, General Abrams decided that the enemy offensive had in fact begun. MACV brought to bear on the enemy buildup everything it had—within the still restrictive rules of engagement. Tactical air sorties, gunships, and B-52 strikes were brought in practically nonstop. A 48-hour maximum effort was begun, concentrating all available airpower against the B-3 Front in the Vietnam's Central Highlands. Then, after a 24-hour cease-fire for the Tet holiday, the same maximum effort was applied in Military Region 1 in the north.