mexico city u.s. republican presidential nominee donald trump say wednesday mexican president enrique pena nieto discuss trump proposal border wall countries new york businessman demand mexico pay trump pena nieto emerge hour talk presidential palace mexico city deliver statements news media take question discuss wall discuss payment wall late date preliminary meet excellent meet trump say pena nieto statement say border must see asset region say undocumented immigration mexico unite state drop considerably since reach peak decade ago trump say mexican leader discuss border wall pay