Alan Garcia, a former president, had an advantage of fewer than 110,000 ballots on Saturday over Lourdes Flores, a pro-business former congresswoman, as Peruvians waited to see who will face nationalist Ollanta Humala in the presidential runoff.
Garcia received 24.4% of the votes counted from April 9 elections, leading Flores by slightly less than 1 percentage point with more than 89% of votes tallied.
Because no candidate won a majority, either Garcia, 56, or Flores, 46, will advance to a second round in late May or June against Humala, a 43-year-old populist retired army officer.
Humala, who identifies with Hugo Chavez, the Venezuelan president, was the top vote-getter on Sunday, with 31%.
Flores closed in on Garcia by 3,824 votes on Saturday, but remained 108,318 ballots shy of second place.
A final outcome was expected to take up to two weeks to deliver because of more than 7,700 vote-tally sheets - representing about 8.5% of the total ballot, or about 1.5 million votes - that have been held up by legal challenges, arithmetic errors and technical problems.
Those disputed sheets are now in the hands of special committees of the National Election Board, which will rule on whether they are added to the count.
Election officials said some ballots were still arriving from isolated rural areas, where Humala enjoys strong support.
Most of the 250,000 ballots cast by Peruvians living abroad also remained uncounted. Early results indicated support leaning heavily toward Flores among expatriates.
Garcia's Aprista party on Saturday announced it would drop a request to annul about 50,000 ballots cast in Miami and Madrid, Spain, because of alleged irregularities.
Garcia called on his party to drop the challenge, saying he wanted “nothing to cloud” the legitimacy of what his party expects will be a victory over Flores by as few as 35,000 votes.
Flores, in her second presidential campaign, is the first woman to make a serious bid for the presidency, but has had a hard time deflecting depictions of her as the candidate of Peru's rich, white elite.
Garcia is seeking a second chance to govern after a 1985-90 administration marked by hyperinflation and a bloody insurgency by Maoist Shining Path guerrillas.