SAO PAULO -(Dow Jones)- Opposition leader Jose Serra, governor of Brazil's biggest state of Sao Paulo, said Friday for the first time publicly that he will be a presidential candidate in this year's elections.

In an interview with the Bandeirantes television network, Serra said he will formally announce his presidential candidacy at the beginning of next month. "It's set for early April," Serra said.

Leaders of the opposition Social Democratic Party have already cleared the path for Serra. There are no other declared candidates for the party's nomination, which is likely to be handed to Serra by acclamation at a party convention in June.

Serra said he will resign as Sao Paulo governor on April 3. Under Brazilian law, Serra must relinquish the post by that date in order to run in the October elections.

Serra will face off against Dilma Rousseff, the chief-of-staff of Brazil's popular President Luiz Inacio Lula da Silva. Rousseff will also resign her post on April 3.

The ruling Workers' Party has already endorsed Rousseff as its presidential candidate. If elected, she would be Brazil's first woman president.

A poll released earlier this week by the Public Opinion Research Institute showed Serra with a modest lead over Rousseff, polling 35% to Rousseff's 30%. But Serra's total shrank from a similar poll in December, when he garnered 38% of voter intentions against only 17% for Rousseff.

"For now, my name appears first, but it's only a poll, a snapshot of the moment," Serra told a Bandeirantes TV interviewer. "Brazilians will only start focusing on the election after the World Soccer Cup is over."

Brazil is a favorite to win the soccer championsnip, which will be played in South Africa in June and July.

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