MEXICO CITY (AP) - Mexico's conservative National Action Party said Thursday it has "strong and conclusive evidence of the use of illicit funds" in the campaign of the winner of the July 1 presidential election, Enrique Pena Nieto.
National Action leader Gustavo Madero said his group is joining with the country's leftist parties to demand electoral authorities investigate the use of pre-paid debit cards purportedly used by Pena Nieto's campaign to distribute an estimated $8.2 million. That would be about a third of all the money he was legally allowed to use in the race.
Pena Nieto of the old ruling Institutional Revolutionary Party, or PRI, won the election with about a 6.6 percentage-point lead over the second-place finisher, leftist Andres Manuel Lopez Obrador.
National Action and Lopez Obrador's Democratic Revolution Party normally don't agree on much, so Thursday's joint news conference between Madero and Democratic Revolution party leader Jesus Zambrano was a rare occurrence.
Both parties claim there was widespread vote buying by Pena Nieto.
National Action first discovered the pre-paid debit cards, which allegedly were used to pay PRI district representatives thousands of pesos. Lopez Obrador's party later uncovered dozens of receipts for mass purchases of the cards. Those receipts listed addresses for apparent front companies, but one of the addresses on the receipts is the same as the office of a prominent former PRI official and lawyer.
"Every day it is becoming clearer ... the link between this money and PRI activists and Enrique Pena Nieto," Madero said.
No big-name PRI member is listed on the receipts, which Lopez Obrador's campaign made public Wednesday. But a receptionist at a phone number listed for one company that bought the cards confirmed a man identified as a Pena Nieto supporter worked there. She refused to give her name and said she had been forbidden from providing any further information.
The PRI has denied it engaged in campaign overspending or vote buying.
On Thursday, leaders of a student movement called "I Am 132" that sprang up before the July 1 elections to oppose campaign violations and the PRI's return presented a resolution that warns of "a serious risk of social explosions" if the electoral courts uphold the election results.
The movement's leadership commission said the resolution must be approved by its national convention at the end of July, but commission member Edgar Tafoya expressed confidence that members will approve the position calling for marches and petition drives to press its demands.
More radical farm and labor groups say they are planning to block highways and government offices to prevent Pena Nieto from taking office Dec. 1. Tafoya said the student convention will consider those plans.
The National Action Party, whose candidate came in third in the presidential race, has recognized its defeat and says it won't ask to have the elections results overturned in court. President Felipe Calderon, who belongs to National Action, has met with Pena Nieto and promised a smooth transition if the courts uphold his victory.
But Lopez Obrador's party has filed a challenge with an electoral court seeking to have the vote annulled.
Madero also said that before declaring the elections valid, electoral authorities must investigate whether front companies bought the debit cards to hide the origin of the money. He also called on electoral authorities to investigate any cash payments made by state governments during the campaign.