A contender for a nomination in next year's presidential election in Mexico has dropped out of the race, amid corruption allegations against him.

Former state governor Arturo Montiel said Thursday he would not seek the nomination from the Institutional Revolutionary Party, or PRI.

The decision came amid news reports that officials were investigating more than $3 million in deposits into the bank account of one of his sons, and probing the family's property deals.

His rival, Roberto Madrazo, is now seen as the PRI's likely presidential nominee.

PRI had ruled Mexico for 71 consecutive years, until Vicente Fox of the National Action Party was elected president in 2000.

President Fox is ineligible to run again, as Mexico's constitution limits presidents to a single six-year term.

Opinion polls indicate former Mexico City Mayor Andres Manuel Lopez Obrador, a leftist party candidate, leads all hopefuls in the election.