LIMA, Peru — President Alberto Fujimori headed to a lopsided victory in an election boycotted by his challenger, who urged thousands of his supporters gathered in the capital to peacefully resist the election's outcome.
Hundreds of demonstrators tried to march toward the presidential palace late Sunday, but riot police drove them back with tear gas. There were no immediate reports of injuries, and tens of thousands of Fujimori foes demonstrated peacefully nearby.
With just over half of the vote counted, Fujimori had 50.3 percent of the ballot to Alejandro Toledo's 16.2 percent, election officials said late Sunday, adding that 32.4 percent of the ballots had been defaced and 0.8 percent left blank. Final results were expected Wednesday, at the earliest.
Promising jobs and capitalizing on his Indian appearance, Toledo made a surprising surge in the first round of voting April 9. But Fujimori fought back, depicting the U.S.-trained economist as a populist who would plunge the country back into the political chaos and hyperinflation of the 1980s.
Foreign monitors withdrew before the election after warning that a fair vote could not be guaranteed. They wanted to delay Sunday's runoff to be able to evaluate new software for tabulating votes, but election officials refused, prompting international criticism.
Tens of thousands of Toledo supporters massed Sunday on a central Lima plaza in a nighttime outpouring to shout their opposition to a Fujimori victory.
From there, a breakaway group of hundreds of students marched toward Fujimori's official residence, the palace, but were repeatedly driven back amid tear gas. Some 1,000 riot police guarded the palace before the protests began subsiding.
The demonstrators set garbage ablaze in the streets and vandalized ATM machines and public telephones.
On the San Martin Plaza six blocks away, the scene was peaceful.
"I've come to tell the people of Peru, 'Enough of this dictatorship!' " said Toledo, 54, addressing a roaring, festive crowd from a podium overlooking the plaza. "Fujimori has taken off his mask and killed democracy in Peru!"
He reiterated calls for "peaceful resistance" to Sunday's election results after a day in which riot police fought Fujimori opponents in sporadic street clashes in downtown Lima. Only a few officers watched the crowd on the plaza as Toledo said: "Let's not be provoked to violence."
Demonstrators waved banners reading "No to Fraud!" while chanting, "The dictatorship will fall!"
Pro-Toledo rallies were reported elsewhere nationwide, and one march by 30,000 people in the central Andean city of Huancayo turned violent when vandals broke the windows of public offices.
The events unfolded after a largely peaceful vote in which long lines formed outside polling stations nationwide.
Toledo, who said he did not cast a ballot, had originally urged Peruvians to boycott the runoff election. But voting is compulsory, and he later told voters to spoil their ballots by scrawling on them: "no to fraud." Failure to vote is punishable by a $33 fine in a country where the monthly minimum wage is less than $120.
Fujimori gave no speech and made no public appearance Sunday after the voting ended.
"This is an election in which there are two candidates because Mr. Toledo has not withdrawn," he said, noting Toledo was still on the ballot despite his boycott and unsuccessful attempts to have his photo and name removed.
Fujimori, 61, who came to power in 1990, counted on Peru's poor majority to help him win. His support is solid in the sprawling shantytowns on Lima's outskirts, where he has paved streets, installed electricity, built schools and provided soup kitchens for the poor.
During the first round of voting, Fujimori won 49.9 percent of the ballot, just shy of the majority he needed to avoid a runoff against Toledo, who collected 40.2 percent and afterward complained that fraud prevailed. Election officials were unable to explain how the number of ballots cast exceeded the number of voters by more than 1.4 million.