Colombians are heading to the polls Sunday to elect a new president, with six candidates vying to govern the country until 2022.
Polling stations opened at 8 am and a total of 36.2 million people are eligible to cast ballots.
Among the presidential candidates are Ivan Duque, of former President Alvaro Uribe's Democratic Center party and currently leading in the voter surveys, as well as Gustavo Petro with the left-wing Colombia Humana party and Sergio Fajardo, representing the center-left Coalicion Colombia.
Also contending for the presidency are German Vargas Llera, of the center-right Mejor Vargas Lleras movement, Humberto de la Calle, of the Liberal Party and Jorge Antonio Trujillo, representing Todos Somos Colombia.
President Juan Manuel Santos urged Colombians to vote "for the good of future generations" in choosing his successor and spoke with reporters after voting with first lady Maria Clemencia Rodriguez and their children in Bogota.
Uribe, for his part, said Duque has a "mixture of steadfastness and decency" that will serve him well in governing Colombia.
"I voted out of love for Colombia," Uribe, who governed from 2002 to 2010, said. "I voted for Ivan Duque due to his youth, intellectual lucidity, education, depth, democratic convictions, his security program, his respect for the law, the incentive (he offers) to the private sector, his (proposed) construction of equity, his willingness to achieve a grand social understanding in Colombia."
Sunday's presidential elections will be the first since the demobilization of the Revolutionary Armed Forces of Colombia (FARC) guerrilla group and are taking place during an ongoing 101-day cease-fire declared by the National Liberation Army (ELN) rebel group.
Polling stations will close at 4 pm and it is expected that the national elections agency will have definitive results available about two hours later.
If none of the candidates obtains at least half of the votes plus one, the presidency will be contested by the two top vote-getters in a June 17 runoff election.