The offensive was launched prematurely in the late night hours of 30 January in the I and II Corps Tactical Zones of South Vietnam. This early attack allowed allied forces some time to prepare defensive measures. When the main operation began the next morning, the offensive was countrywide and well coordinated; eventually more than 80,000 PAVN/VC troops struck more than 100 towns and cities, including 36 of 44 provincial capitals, five of the six autonomous cities, 72 of 245 district towns, and the southern capital. The offensive was the largest military operation conducted by either side up to that point in the war.