LAUSANNE, Switzerland — Wrapping up six days of marathon nuclear talks with mixed results, Iran and six world powers prepared Tuesday to issue a general statement agreeing to continue negotiations in a new phase aimed at reaching a comprehensive accord by the end of June, officials told The Associated Press on Tuesday. The joint statement is to be accompanied by additional documents that outline more detailed understandings, allowing the sides to claim enough progress has been made thus far to merit a new round, the officials said. One of the officials said the statement was general in part because differences...