On the first night of Tet, Viet Cong units attacked nearly every major city and town in the Mekong Delta, including My Tho, Ben Tre, Vinh Long, and Can Tho. Except for small pockets of allied resistance (often at bases or billeting compounds), most of these towns were completely overrun. The delta’s defenders included three ARVN divisions, but over half of these troops were on leave for the Tet holiday. Effectively, this meant that a large portion of the fighting would fall upon the U.S. Army 9th Division and naval forces. Riverine units performed two basic functions during the attack: mobile fire power and transport for Army troops.