The council issued its results Sunday after counting 91.68 percent of the ballots. if no candidate gets 50 percent, a second round in the presidential election will take place June 17.
Colombia held its first election since a peace agreement was signed with the Revolutionary Armed Forces of Colombia (FARC) in 2016.
The region has long suffered from the activities of US-supported Colombian rebel groups. In 2016, the government of Colombian President Juan Manuel Santos hammered out a peace deal with FARC, transforming the militant group into a political party the following year. Around 1,200 former FARC insurgents are believed to have joined drug-trafficking factions, including the Oliver Sinisterra Front.
Some areas abandoned by FARC saw a brief increase in violence due to the internecine skirmishes between local criminal gangs and remaining guerrilla groups, while the National Liberation Army (ELN) reported illegal mining and drug trafficking.
According to Reuters, it was the fist time in Colombia's modern history that a leftist candidate has reached the second round of a presidential election.