BOGOTA, Colombia (AP) — Former rebel Gustavo Petro narrowly won a runoff election over a political outsider millionaire Sunday, ushering in a new era of politics for Colombia by becoming the country’s first leftist president.

Petro, a senator in his third attempt to win the presidency, got 50.47 percent of the votes, while real estate magnate Rodolfo Hernández had 47.27 percent, with almost all ballots counted, according to results released by election authorities.

Petro’s victory underlined a drastic change in presidential politics for a country that has long marginalized the left for its perceived association with the armed conflict.

“Today is a day of celebration for the people. Let them celebrate the first popular victory,” Petro tweeted. “May so many sufferings be cushioned in the joy that today floods the heart of the Homeland.”

Petro was once a rebel with the now-defunct M-19 movement and was granted amnesty after being jailed for his involvement with the group.

At his headquarters in the capital city of Bogota, a message on a screen read, “Gracias Colombia,” or “Thank you Colombia.”

Outgoing conservative President Iván Duque congratulated Petro shortly after results were announced, and Hernández quickly conceded his defeat.

“I accept the result, as it should be, if we want our institutions to be firm,” Hernández said in a video on social media. “I sincerely hope that this decision is beneficial for everyone.”

The vote came amid widespread discontent over rising inequality, inflation and violence — factors that led voters in the election’s first round last month to turn their backs on the long-governing centrist and right-leaning politicians and choose two outsiders in Latin America’s third-most populous nation.

Petro’s showing was the latest leftist political victory in Latin America fueled by voters’ desire for change. Chile, Peru and Honduras elected leftist presidents in 2021, and in Brazil, former President Luiz Inácio Lula da Silva is leading the polls for this year’s presidential election.

About 21.6 million of the 39 million eligible voters cast a ballot Sunday. Abstentionism has been above 40 percent in every presidential election since 1990.

Petro, 62, will be officially declared winner after a formal count that will take a few days. Historically, the preliminary results have coincided with the final ones.

Polls ahead of the runoff had indicated Petro and Hernández — both former mayors — were in a tight race since they topped four other candidates in the initial May 29 election. Neither got enough votes to win outright and headed into the runoff.

Petro has proposed ambitious pension, tax, health and agricultural reforms and changes to how Colombia fights drug cartels and other armed groups.