Mexico's ruling conservatives pump up attacks on rival

MEXICO CITY (Reuters) - Mexico's ruling conservatives have stepped up attacks on presidential front-runner Enrique Pena Nieto in an effort to help their struggling candidate, who is slipping back toward third place.

A new TV spot by the National Action Party, or PAN, describing Pena Nieto as a "liar" began to circulate just as a poll showed support for PAN contender Josefina Vazquez Mota falling to its lowest level since the campaign began.