NBC News anchor Brian Williams has canceled a planned appearance with late-night talk show host David Letterman this week, an NBC News source said on Sunday, the latest fallout over misstatements by Williams over his experience reporting on the Iraq war. Williams, a star anchor who has garnered high ratings for NBC, said on Saturday that he would voluntarily take himself off the evening newscast for several days while his network looks into the issue. NBC, a unit of Comcast Corp, on Friday said it was launching an internal probe of Williams over his statements that he was aboard a helicopter in 2003 that was brought down by enemy fire during the U.S. invasion of Iraq.
