Former investment banker Pedro Pablo Kuczynski had a wafer-thin lead on Tuesday over rival Keiko Fujimori in the latest tally from Peru's presidential race, with tens of thousands of votes from abroad and in remote jungle villages still to be counted.
The results in Peru's tightest election in at least 50 years gave Kuczynski a 0.34 percentage point edge over Fujimori, the daughter of a jailed former president.
Europe were still trickling in would likely decide the election.
A partial count suggested they would favor Kuczynski, a 77-year-old former prime minister who worked for years on Wall Street.
The margin between the two business-friendly candidates widened to 57,000 votes in the latest update by Peru's electoral office, ONPE, two days after polls closed.
Preliminary results on Sunday and quick counts of sample ballots by reputable polling firms had put Fujimori, the daughter of jailed ex-President Alberto Fujimori, behind Kuczynski by about one percentage point.
"We're optimistic," Kuczynski told reporters as he headed to a country club in Lima's financial district to work out.
With the race so close, Fujimori, who has largely been out of the public eye since Sunday, does not plan to accept possible defeat until 100 percent of the votes are counted, a person close to the candidate said on condition of anonymity.
TV images showed Fujimori smiling and waving from a car on Tuesday.
With 97 percent of the ballots counted two days after the election, Kuczynski won 50.17 percent of valid votes compared with Fujimori's 49.83 percent, according to ONPE.
More ballots than that - 98.7 percent - had been processed, but about 1.7 percent of them were being questioned due to lack of clarity and would be settled by local electoral panels.
"We have to be very cautious," said Mariano Cucho, the head of ONPE, in broadcast comments. He said a full ballot count will probably not be finished until the weekend.
Ballots, mostly from Peruvians living in the United States and Europe, were still arriving, according to ONPE. A count of about 80 percent of U.S. votes showed Kuczynski with an eight-point lead over Fujimori, and a partial count of votes from Europe showed Kuczynski had a bigger advantage.
Market reaction has been muted, as both candidates would
continue the country's free-market economic model in the mineral-rich Andean nation.
A week ago, Fujimori had been the favorite to win. But Kuczynski caught up with her in final opinion polls as Peruvians weighed the legacy of her father, who was convicted of corruption and human rights abuse, and scandals involving her own close advisers.
Some Peruvians credit the elder Fujimori with defeating violent Shining Path guerillas and building rural schools during his decade-long rule.
Kuczynski has promised to invest in infrastructure projects and lower sales taxes to revive economic growth that has slowed with tumbling mineral prices.