Keiko Fujimori, the daughter of an ex-president jailed for massacres, has won the first round of voting in Peru's presidential election, partial results showed.
Fujimori won 38 percent of votes in line with exit polls, with one fifth of votes counted, the electoral body said. Rival Pedro Pablo Kuczynski had 24.5 percent.
Since Fujimori fell short of 50 percent, though, she must now face Kuczynski in a runoff on June 5.
Fujimori had earlier celebrated victory as unofficial surveys showed her far in the lead.
Voters "are demanding change. This is a great responsibility, which we are going to honour," she told cheering supporters.
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"Peru wants reconciliation and no more conflict. We invite all Peruvians on June 5 to opt for change and for the future, because the future of Peru is on the way."
Observers complained that the electoral process was undermined when half the candidates dropped out or were excluded from running under a tough new electoral law.
Keiko survived attempts to ban her from the race amid mistrust over her father's legacy.
She and other leading candidates were accused of wooing voters with gifts. Both she and Kuczynski were cleared of the charges.
A dark decade
But centrist candidate Julio Guzman, previously second in the polls, was banned from running for irregularities in the candidate selection process.
Eight other candidates were similarly excluded or dropped out through lack of support.
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European Union observers said they saw no serious incidents during voting, though some polling stations opened late.
Alberto Fujimori's dark decade in power from 1990-2000 lives in the memory of many Peruvians.
Now 77, he is serving a 25-year jail sentence for crimes against humanity. The courts held him responsible for the massacre of 25 people he said were terrorists in 1991 and 1992.
But many voters love him for crushing the Shining Path armed group that carried out attacks and kidnappings.
Source: Al Jazeera and agencies