Mexico's Federal Electoral Institute has confirmed that the country's new president's party spent more than $5 million through electronic cash cards during last year's presidential campaign.

Opposition parties say the money represented illicit campaign financing, but the institute said it found no evidence of that. President Enrique Pena Nieto's Institutional Revolutionary Party has said the money was used for normal party personnel expenses, but the funds raised suspicions, because the money wasn't dispersed directly from party coffers. Opponents also said they suspected that corporations may have used the cards to make campaign donations, something that is prohibited under Mexican law.

The Federal Electoral Institute's board voted 5-4 that the funding did not necessarily represent a campaign violation, though critics said the institute did not take the trouble to investigate thoroughly where the money came from. The institute, Mexico's top electoral oversight agency, is scheduled to rule on possible campaign overspending by late January. Campaign overspending can result in fines but not reversal of the election results.