The US army officer convicted for his part in the notorious My Lai massacre during the Vietnam War has offered his first public apology, a US report says. "There is not a day that goes by that I do not feel remorse for what happened," Lt William Calley was quoted as saying by the Columbus Ledger-Enquirer. He was addressing a small group at a community club in Columbus, Georgia. Calley, 66, was convicted on 22 counts of murder for the 1968 massacre of 500 men, women and children in Vietnam