BOGOTA, Colombia (AP) -- Juan Manuel Santos convincingly won re-election Sunday after Colombia's tightest presidential contest in years, an endorsement of his 18-month-old peace talks to end the Western Hemisphere's longest-running conflict.
Santos got 53 percent of the votes for candidates, against 47 percent for right-wing challenger Oscar Ivan Zuluaga, the hand-picked candidate of former two-term President Alvaro Uribe, who many considered the true challenger. More than 600,000 voters cast "blank" ballots, a protest vote for neither candidate.
Zuluaga and Uribe accused Santos of selling Colombia out in slow-slogging Cuba-based negotiations, and said Zuluaga would halt the talks unless the rebel Revolutionary Armed Forces of Colombia, known as the FARC, ceased all hostilities and some of its leaders accepted jail time.
Santos said the win affirmed his claim to be ably steering Colombia through a historic moment -- out of a crippling conflict that has claimed more than 200,000 lives, mostly civilians.
"This is the end of more than 50 years of violence in our country and it is the beginning of a Colombia with more justice and social inclusion," Santos told cheering supporters. "In four years no one will regret having voted for us."
He flashed his palm emblazoned with the word "Paz," or peace -- his campaign slogan. Many palms in the crowd were similarly inscribed.
A FARC spokeswoman in Havana said the rebels had no comment on the election's results.
The campaign was Andean nation's dirtiest in years, and Uribe alleged widespread vote-buying by the Santos camp. After Santos' victory speech, he stunned the nation by appearing on TV to accuse the winner of "the biggest corruption in history."
Uribe also alleged that leftist rebels used armed intimidation against pro-Zuluaga voters. He presented no evidence, and independent election observers did not report serious irregularities.
Zuluaga made no such claims in a gracious concession speech two hours earlier. The Associated Press could not immediately reach him or his campaign to ask if they endorsed Uribe's accusations.
Santos' win was a comeback of sorts -- Zuluaga beat him in the first round of five candidates May 25. His 900,000-vote victory hinged in large part on winning Bogota and major gains on the Caribbean coast, where his party machinery was strong. The region does indeed have a tradition of vote-buying.
In the first round, Santos finished third in the capital, stronghold of defeated leftist candidate Clara Lopez, who endorsed him in the runoff.
Voter turnout rose somewhat, too, from 40 percent in the first round to 48 percent Sunday, and was seen as favoring Santos.
The University of Kansas-educated incumbent got the backing last week of 80 top business leaders and announced exploratory talks with the National Liberation Army, Colombia's other, far smaller rebel band.
Uribe had accused Santos, grandnephew of a president from a blue-blood Bogota newspaper clan, of offering impunity to the rebels.
Bogota industrial designer Felipe Quintero said he voted for Zuluaga, a previously little-known finance minister, because Santos was conceding too much to rebels.
"They need to be punished, not to be rewarded" with seats in Congress, Quintero said.
Santos, 62, denies he will let war criminals go unpunished.
And he is no dove. As Uribe's defense minister and then president, he wielded Colombia's U.S.-backed military to badly weaken the FARC, including killing its top three leaders.
Analyst Adam Isacson of the Washington Office on Latin America called the election less a vote on the peace process than "a referendum on Alvaro Uribe and his role in Colombian society."
"The eight years he was president were a time of some of the worst corruption and biggest scandals," said Bogota business consultant Maria Eugenia Silva, who voted for Santos.
A victory for Zuluaga would have lessened chances that Uribe might face prosecution for alleged crimes. Blemishes of his 2002-10 government included extrajudicial killings of innocent civilians to boost military body counts, illegal spying on judges and journalists and the funneling of agricultural subsidies to well-heeled ranchers.
Uribe, who is constitutionally barred from another presidential run, won a Senate seat in March. But Santos will continue to dominate Congress.
"Even skeptics of the peace process voted with Santos," said Michael Shifter, president of the Inter-American Dialogue think tank. "They didn't want to go back to Uribe-style politics."
Zuluaga was backed by cattle ranchers and by palm oil plantation owners, beneficiaries of a deal Uribe made with far-right paramilitaries that dismantled their militias.
Big landholders had by then consolidated control over territory that the militias largely rid of rebels while driving at least 3 million poor Colombians off their lands. As part of the Santos-negotiated peace process, those stolen lands would be returned.