Mexico’s four presidential candidates have held their final televised debate ahead of the 1 July election, promising to reduce violence and tackle poverty.
Hours earlier, thousands of young people protested in Mexico City against front-runner Enrique Pena Nieto of the Institutional Revolutionary Party.
The PRI ruled Mexico for more than 70 years before being defeated in 2000.
But Mr Pena Nieto, who has a wide lead in the polls, was largely untroubled during the debate, correspondents say.
Sunday’s encounter was one of the last chances for the other candidates to make a dent in his lead.
Josefina Vazquez Mota, of the governing National Action Party (PAN), went on the attack, saying both Mr Pena Nieto and Andres Manuel Lopez Obrador represented the past.
“You, young people, you can rally in the streets without fearing an authoritarian president,” she said.
She accused Mr Pena Nieto of hiding in the bathroom after students heckled him during a campaign event at a university in May.
Mr Pena Nieto denied he had done so and said he welcomed the participation of students in the political process.
“I faced the groups that expressed themselves legitimately against me. It’s a voice I respect,” he said.
There have been student-led demonstrations in the past few weeks against Mr Pena Nieto and the PRI, with demonstrators attacking what they say is the uncritical coverage of his campaign by the main TV network, Televisa.
On Sunday, some 90,000 people gathered in Mexico City’s main square, the Zocalo, to protest against the PRI.
Many carried signs of the “#yosoy132″ (I am the 132) movement, a reference to the initial group who heckled Mr Pena Nieto.
Some also carried signs commemorating the killing of a dozen students by pro-government agents during a political demonstration in 1971.
During the debate, Andres Manuel Lopez Obrador of the Party of the Democratic Revolution (PRD) said the current government was “rotten” and it was time for change.
“It needs a definitive renewal of public life, a change in all aspects of public life, changes in economic policies, changes in the way politics is done.”
Opinion polls have consistently given Mr Pena Nieto a double-digit lead over his rivals, although Mr Lopez Obrador has seen a slight surge in support in recent days.
Fourth-placed candidate Gabriel Quadri trails far behind.
The candidates spoke about the need to boost economic growth and tackle poverty and drug violence, but gave few details of how they would achieve this.