In continued efforts to disrupt an anticipated communist offensive, a contingent of more than 10,000 South Vietnamese troops begin a sweep 45 miles northwest of Saigon to find and destroy enemy forces. There was much speculation that the North Vietnamese would launch such an offensive around the Tet (Chinese New Year) holiday. Although the communists did not attack during the Tet holiday in early February, in March they launched a massive invasion involving more than 150,000 main force troops and large amounts of tanks and artillery pieces. The battles raged throughout South Vietnam into the fall and resulted in some of the fiercest fighting of the war.