Brasil, Brazil - Luiz Inácio Lula da Silva, the left-wing former president, has won the first round of Brazil's presidential election and will face incumbent Jair Bolsonaro in a run-off vote.

Lula came in at 47.97%, while the far-right Bolsonaro received 43.60%, the electoral office announced Sunday.

Since no candidate won more than 50% of the vote, Lula and Bolsonaro as the two strongest contenders will go to a runoff on October 30.

The result was much closer than expected, as pre-election polls had Lula far ahead. Some experts suggested respondents had not declared their true favorites or made up their minds on election day.

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If Lula wins the second round, he would be Brazil's first democratic president to enter a third term. He was previously president from 2003-2010.

Many of Lula's supporters associate the 76-year-old with Brazil's golden age, when the economy boomed due to high commodity prices and the government used social programs to lift millions out of abject poverty.

Opponents accuse him of corruption and cronyism, while Bolsonaro's base sees the incumbent as a defender of traditional family values and business.

The election has left Latin America's largest economy extremely divided.

At least three Lula supporters have been killed by suspected Bolsonaro supporters, and the right-wing movement has sometimes openly called for a military coup, as well threatening to reject unfavorable election results.

During his four years in office, Bolsonaro has largely isolated Brazil internationally, rejecting proposals to protect the rainforest and hardly ever travelling abroad, all while presiding over a catastrophic response to the Covid-19 pandemic, which has killed over 686,000 people in the country.

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Brazil's election has great significance for the rest of the world, as the winner will shape the country's environmental policies. As a huge carbon sink, the Amazon plays an important role in the fight against global climate change.

Lula campaigned on environmental and climate policies and pledged to end illegal gold mining and fight against deforestation.

More than 156 million people were eligible to vote in Sunday's presidential election and voting is compulsory. Lawmakers, senators, and governors were also being elected on the same day, with results somewhat favoring the right wing.