Colombian leftist Gustavo Petro won the most votes in the country's presidential election on Sunday but not enough to avoid a runoff.
Petro will face a surprise contender, businessman Rodolfo Hernandez, in the second round in June.
"What's not in doubt today is change," Petro told cheering supporters in central Bogota.
"Now it's about seeing what we will do with Colombia, what Colombian society wants for its own country."
Hernandez edged out Federico Gutierrez, who was number two in the polls before the vote and had the support of outgoing President Ivan Duque.
"Today we know citizens have a firm will to end corruption as a system of government," Hernandez said on social media.
"The gangs who thought they would govern forever lost today," he added.
Petro, a senator, secured 40.4% of votes, national registry office tallies showed, while Hernandez won 27.9%. Petro needed 50% of the total votes to have avoided the runoff.
What do the candidates stand for?
Petro has vowed profound economic and social change in Colombia. He has plans to redistribute pensions, make public universities free, and tackle the country's inequality and poverty.
He has also said he will put a stop to new oil and gas projects.
Hernandez, is running on a platform of anti-corruption promises. The 77-year-old is also under investigation for allegedly favoring a company his son had lobbied for.
The businessman has also pledged to strengthen law and order as well as create jobs, but he has shared scant details of those plans.
He rose in the polls only in the last two weeks, boosted by his colorful social media presence.
Hernandez has said he would explore peace talks with the ELN if elected and continue to fulfill the FARC deal.
lo/jsi (AFP, AP, Reuters)