|Humala, right, currently leads the exit polls in a tightly contested presidential election in Peru [EPA]
Peru has voted in a tight presidential runoff between leftist Ollanta Humala and the daughter of the imprisoned ex-president Alberto Fujimori.
The first partial official results released on Monday gave former military commander Humala a narrow lead with 50.087 per cent of the vote.
Similar results had been suggested in several exit polls.
Humala, 48, campaigned on promises of sharing out Peru's rich mineral wealth after a decade of record growth.
He allied himself closely with socialist Venezuelan President Hugo Chavez in his first run for the office in 2006, which he narrowly lost to Alan Garcia. This time he softened his rhetoric and disavowed Chavez, promising instead to follow Brazil's market-friendly model.
Supported by the poor
Humala is backed largely by the one in three Peruvians who are poor and have not benefited from a mining boom that has fuelled economic growth averaging 7 per cent annually since 2001.
Mirko Lauer, a political analyst, told Al Jazeera that "Humala has managed [to win support] by moving to the centre-right to produce a feeling of confidence."
Lauer said that a victory for Humala would be very significant.
"Mr Humala would have to produce a Brazilian-type government that will sort of mix the left in politics with the right in the economy, and produce a type of social policy that will get him across."
A win for Humala would be the first return of the left to power in Peru since the 1968-1975 military regime of Juan Velasco Alvaredo.
Keiko Fujimori campaigned in the shadow of her father, Alberto Fujimori, who is serving a 25-year jail term for corruption and rights abuses during a 1990s crackdown on Shining Path guerrillas.
Almost 20 million Peruvians were eligible to vote for a successor to centre-right President Alan Garcia.