By Mario Naranjo and Andrew Cawthorne
CARACAS (Reuters) - Venezuelan President Hugo Chavez on Monday declared himself fully recovered from cancer and ready to return to the streets for his re-election campaign ahead of an October vote.
"Free, free, totally free," an ebullient Chavez told reporters when asked if he was free of the disease that struck a year ago.
The 57-year-old socialist leader, who has dominated the South American OPEC member since taking power in 1999, was first diagnosed with cancer in the pelvic region in the middle of last year.
He wrongly declared himself cured at the end of 2011 and suffered a recurrence of the disease in February.
But after three operations in a year and repeated cycles of treatment in Cuba and Venezuela, Chavez is once again declaring himself fully fit at a crucial time when his health is the main wild card before the October 7 presidential vote.
Despite his optimism, doctors say it is impossible to be sure someone is completely cured of cancer until at least a couple of years have passed since the last recurrence.
Perceptions of Chavez's ability to campaign for the election, and govern afterwards, may play a decisive role in what could be one of Venezuela's tightest elections of recent times.
The former soldier is leading most opinion polls by double digits, but one recent survey put him neck-and-neck with opposition candidate Henrique Capriles and as many as a third of voters remain undecided.
At a more than four-hour news conference that offered more evidence of Chavez's increasing energy levels, he promised to begin campaigning on the streets with a series of caravans around the nation from Thursday.
"Now is when I'm stepping into the action. Our offensive begins right now!" said Chavez, who disappeared for long periods during treatment over the last year but has been back dominating Venezuela's airwaves in recent weeks.
"Chavez is back in the street, the Bolivarian hurricane!" he added, referring to his idol and Venezuela's independence hero, Simon Bolivar.
Chavez has tested the waters in the last month with two carefully staged appearances riding through crowds in open-topped trucks. On both occasions, he whipped up crowds by waving and blowing kisses, but did not actually walk on the streets.
Capriles, a 39-year-old, center-left former governor, has been criss-crossing Venezuela on a "house-by-house" tour in a show of youth and energy that the opposition has been using to contrast with the ailing Chavez.
The president, though, who was famous for his whirlwind on-the-street campaigning of the past, appears to be recovering his energy levels.
"Every day, I feel in better physical condition and I strongly believe ... it is not going to be a determining factor in this campaign," he told reporters. "I'm a veteran of 100 battles and I feel in great moral, spiritual and physical conditions for this fight that is starting."
Capriles held a news conference minutes after Chavez wound up, mocking his verbose style and longevity in office in a newly combative style he hopes will win votes.
"We're tired of the blah-blah, of the offensive language ... The pitcher looks tired," Capriles said, using the baseball imagery often employed by the sports-loving president.
It is not only rhetoric that is heating up on both sides.
Police intervened over the weekend to block a Capriles campaign stop in a Caracas slum after his and Chavez's supporters confronted each other in the street.
Underlining fears of violence in the deeply polarized nation of 29 million people, stones and bottles were thrown, with several people said to be injured during the fracas on Saturday.
The stakes are big not only for Venezuela, which has the largest oil reserves in the world, but also for the wider region.
Political allies from Cuba to Bolivia depend on Chavez's oil-financed largesse. Washington, too, is watching quietly to see if its fiercest critic in Latin America wins an election that would potentially extend his rule to 20 years.
(Additional reporting by Brian Ellsworth, Diego Ore, Eyanir Chinea and Silene Ramirez; Editing by Kieran Murray and Cynthia Osterman)