WASHINGTON (AFP) – ABC News has apologized after a high-profile news anchor reported on Twitter that US President Barack Obama called rapper Kanye West a "jackass" in an off-the-record conversation. The exchange, provoked by West's conduct at the MTV Video Music Awards when he interrupted an acceptance speech by teen star Taylor Swift, occurred during a break between a series of interviews by Obama at the White House Monday. The comment, from an off-the-record portion of an interview by US business channel CNBC, was tweeted to one million followers on the micro-blogging site by "Nightline" anchor Terry Moran. The tweet...