The Commitment to Mexico coalition, made up of the Institutional Revolutionary Party, or PRI, and the Mexican Green Party, has responded to the challenge filed by the leftist Progressive Movement to the results of the presidential election.

"To clear up any doubts, to defend legality and the institutions, today we are going to begin the legal defense of our electoral victory on Sunday, July 1," PRI chairman Pedro Joaquin Coldwell said Monday.

The coalition led by the PRI "is not going to allow allegations of being corrupt" to be leveled at the millions of citizens who voted "in secret, freely and with dignity," Coldwell said.

Commitment to Mexico candidate Enrique Peña Nieto won the presidential election with 38.21 percent of the vote, while Progressive Movement standard-bearer Andres Manuel Lopez Obrador took second place with 31.59 percent, according to the final official results released by the Federal Electoral Institute, or IFE.

Lopez Obrador, who was the candidate of a coalition of leftist parties led by the Party of the Democratic Revolution, or PRD, filed a challenge last week to the election results.

The election was marred by vote buying and therefore there is no "certainty for any result nor for the electoral process as a whole," Lopez Obrador said in a press conference last Thursday.

Coldwell, for his part, defended his coalition against the "allegations and lies" from the left, calling the recent election "the cleanest" in Mexico's history and "a festival of democracy" that allowed citizens to cast "informed and reasoned" ballots.

"The only fraud in this election is wanting to invalidate the legitimate, free and secret votes of more than 50 million Mexicans without evidence or legal reasons," Coldwell said.

Campaign spending limits, contrary to Lopez Obrador's allegations, were never exceeded and election officials have the documents to back this up, the PRI chairman said.

The candidates all had "sufficient and equitable" access to the media, allowing them to have equal coverage, Coldwell said in response to allegations of partiality in media coverage.

"It is insulting to Mexicans to argue that the media has the power to impose a candidate on voters," the PRI chairman said.

The polls were not manipulated and state governors did not interfere with the electoral process, Coldwell said, adding that no parallel financing systems were created by the PRI.

"The origin of the campaign funds is legal, we strictly followed the campaign limits set by the law, funds were spent in accordance with the law and no money was diverted to buy votes as is being falsely alleged," the PRI chairman said.

Lopez Obrador alleged that the PRI may have bought up to 5 million votes, a charge that Coldwell said was "false and will go down on its own."

The allegation "is absurd that one of every 10 votes was bought. If it were like that, there would be millions of witnesses, when the only thing we have are 50 million voters who exercised their political rights with dignity," Coldwell said.

The IFE is expected to submit both the Progressive Movement's challenge and the PRI's response to the TEPJF electoral court on Tuesday.

The TEPJF electoral court has until Sept. 6 to review the documents and either certify Peña Nieto as president-elect or call for new elections.

The PRI, which governed Mexico from 1929 to 2000, lost the 2000 and 2006 presidential elections to the conservative National Action Party, or PAN.

During its 71 years of largely unchallenged hegemony, the PRI relied mainly on patronage and control of organized labor and the mass media, though it was not above resorting to outright vote-rigging and even violence. EFE