Thousands of people have taken to the streets in the Mexican capital against President-elect Enrique Pena Nieto, accusing him of buying votes.
Demonstrators marched through Mexico City on Saturday, shouting slogans against Pena Nieto's Institutional Revolutionary Party (PRI).
The protesters -- among them students, leftists, anarchists and union members -- responded to a call by leftist activists who had called for a “mega march” after the official count announced Pena Nieto winner of the July 1 election by almost 7 percentage points.
The protesters shouted slogans against the country’s electoral authority and Pena Nieto, accusing the former state governor of paying off TV networks for support.
Pena Nieto's victory returned presidential power to the PRI after 12 years. The party once ruled Mexico for seven decades, a period marked by vote rigging and consequent crackdown scandals.
Pena Nieto is scheduled to take office in December, replacing Felipe Calderon of the conservative National Action Party (PAN) who is barred by the constitution from running for a second term.
Meanwhile, Calderon’s failed campaign against drug-related crimes and the country’s sluggish economic growth under his government discouraged voters from choosing the PAN candidate, Josefina Vazquez Mota, who finished third.
Leftist Andres Manuel Lopez Obrador ended up in second place but has refused to admit defeat, accusing Pena Nieto of stealing the presidency.
Pena Nieto denies allegations of electoral fraud and PRI officials have threatened to sue Lopez Obrador over the accusations.
Lopez Obrador, who led major protests after the 2006 presidential polls, has so far avoided calling for protests directly. He has, however, said he is collecting evidence of fraud to give to officials and called on the PAN to join forces with him to take legal action.
Mexico's electoral tribunal is to evaluate any complaints by September and officially name the country’s new president.