'It's going to be pretty close': Sanders

The search for a Democrat to challenge Republican U.S. President Donald Trump in the Nov. 3 election narrowed on Wednesday to a choice between Bernie Sanders and Joe Biden, who staged a comeback in voting Super Tuesday to become the undisputed flag bearer of the party's moderate wing.

Former Vice President Biden unexpectedly won at least nine of the 14 states up for grabs on Tuesday, including the major prize of Texas, and stormed ahead in the overall tally of delegates who will choose a presidential nominee at the Democratic convention in July.