Former Mexico state Gov. Enrique Peña Nieto said he planned to seek the nomination of the opposition Institutional Revolutionary Party, or PRI, for the 2012 presidential election.

"I aspire to be president of the republic," Peña Nieto told Radio Formula on Tuesday.

Peña Nieto has been identified as the favorite to win the July 1, 2012, presidential elections, thanks to his strong showing in public opinion polls.

The 45-year-old politician revealed his plans to seek the presidency just days after handing over power in Mexico state, which surrounds the Federal District and forms part of the Mexico City metropolitan area, to fellow PRI member Eruviel Avila, who swept the gubernatorial election in July.

The PRI, which hopes to regain power after losing two straight presidential elections to the conservative National Action Party, or PAN, plans to lay out the rules for picking a nominee and its platform next month.

Peña Nieto, who favors an open vote by citizens to select the PRI's candidate, said he would work closely with society on his plans and identify "alternatives for resolving" the problems in Mexico.

"We can influence the transformation of the country," the attorney said.

Peña Nieto attributed his soaring popularity to the successes he had in Mexico state, the country's most populous state with 15 million residents and the No. 2 contributor to the gross domestic product.

The politician, who married actress Angelica Rivera last November after losing his first wife in 2007, agreed before a notary to keep the 600 campaign promises he made as a gubernatorial candidate.

The nominating process will take place in a "climate of unity" and amid "great civility" among those running to be the PRI's standard-bearer, Peña Nieto said.

Among Peña Nieto's opponents for the nomination will be Sen. Manlio Fabio Beltrones.

Mexico City Mayor Marcelo Ebrard, who is vying for the presidential nomination of the leftist Party of the Democratic Revolution, or PRD, said he was not surprised that Peña Nieto had decided to run.

"What surprises me is that he took so long, you have to say what you want to do, to be honest and say it upfront like I've said it," Ebrard said.

Ebrard is competing with former Mexico City Mayor Andres Manuel Lopez Obrador in a bid to have only one candidate from the left in the 2012 election.

President Felipe Calderon won the 2006 election by a razor-thin margin over Lopez Obrador, who alleges he was cheated out of the presidency.