Juan Manuel Santos convincingly won re-election after Colombia's tightest presidential contest in years, an endorsement of his 18-month-old peace talks to end the region's longest-running conflict.
Santos won 53 per cent of valid votes, against 47 per cent for right-wing challenger Oscar Ivan Zuluaga, the preferred candidate of former two-term president Alvaro Uribe. More than 600,000 voters cast "blank" ballots on Sunday, a protest vote endorsing neither candidate.
Zuluaga and Uribe accused Santos of selling Colombia out in slow-moving peace negotiations, and said Zuluaga would halt the talks unless the rebel Revolutionary Armed Forces of Colombia (Farc), ceased all hostilities and some of its leaders accepted jail terms.
Santos said the win affirmed his claim to be ably steering Colombia through a historic moment and 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 (peace), which was his campaign slogan. Many palms in the crowd were similarly inscribed.
A Farc official in Havana, Cuba, said the rebels had no comment on the poll result.
The campaign was the Andean nation's most dubious in years, with Uribe accusing Santos of vote-buying. After Santos' victory speech, Uribe 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.
Santos' win was a comeback of sorts after Zuluaga beat him in the first round of five candidates on May 25. His 900,000-vote victory hinged in large part on winning Bogota and major gains on the Caribbean coast, where his party was strong. It is a region that has a tradition of vote-buying.
In the first round, Santos finished third in the capital, the stronghold of defeated leftist candidate Clara Lopez, who endorsed him in the run-off.
Voter turnout was also higher, up from 40 per cent in the first round to 48 per cent on Sunday, and was seen as favouring Santos.
The United States-university educated leader 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.
Bogota industrial designer Felipe Quintero said he voted for Zuluaga 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 would let war criminals go unpunished.