Colombian presidential candidate Ivan Duque (center), of the Democratic Center party celebrates with supporters next to his running mate Marta Lucia Ramirez (right) and one of his daughters (left), after winning the first round of the Colombian presidential election, in Bogota. The conservative candidate won the first round of Colombia's presidential election Sunday but fell short of the 50 percent threshold needed to avoid a runoff next month. The 41-year-old senator will face former guerrilla leader Gustavo Petro on June 17, the first leftist candidate to contest a runoff election in Columbia. Photo: AFP

Colombia's outgoing conservative President Ivan Duque on Monday promised a "transparent and efficient" transition to the new administration led by Gustavo Petro.

Ex-guerrilla Petro, 62, made history on Sunday when he was elected as the first left-wing president in the crisis-torn South American country's history.

But with Duque and Petro occupying polar opposites on the political spectrum, there are fears the transition could be tense.

"Yesterday, we Colombians went to the polls, we expressed our points of view and the first thing one must recognize to defend democracy is the popular will," said Duque on Twitter.

"To the new president @petrogustavo, I expressed my support for a transparent and efficient transition."

Petro garnered 50.4 percent of the vote in Sunday's runoff, with millionaire businessman Rodolfo Hernandez on 47.3 percent, missing out by 700,000 votes.

Hernandez immediately recognized his defeat as Petro ended 200 years of conservative and liberal political dominance.

In his victory speech, Petro promised "real change" for his country, based on "peace, social justice and environmental justice."

Petro celebrated his victory in a huge theater in Bogota while thousands of his supporters descended on a rainy historic square in the center of the capital to rejoice.

The announcement of environmental activist and feminist Francia Marquez as the new vice-president was met with joy in her home town of Suarez in the southwestern department of Cauca.

As the first black woman to be elected to that post, her success was celebrated throughout communities with significant populations of Afro-descent, who make up around 10 percent of the country's 50 million people.

AFP