Colombians heading to presidential polls on Sunday will be faced with choosing between two contrasting candidates: Conservative frontrunner Ivan Duque, who wants to overhaul a peace deal with the FARC rebels, and leftist former mayor and ex-guerrilla Gustavo Petro, who supports the pact. The elections are the first since the agreement was signed in 2016. "We have a country without FARC, which is building peace," President Juan Manuel Santos, who will step down in August, said ahead of the poll. His efforts to end the war with FARC brought him the Nobel Peace Prize, though he is leaving office with record unpopularity in a country of 49 million people. The worlds leading producer of cocaine, the Latin American country continues to battle armed groups vying for control of lucrative narco-trafficking routes in areas FARC once dominated. Duque comfortably won the first round last month, having campaigned on a pledge to rewrite the agreement signed by Santos. Vehemently opposed to the peace deal, 41-year-old Duque says he would revise it in order to sentence guerrilla leaders guilty of serious crimes to "proportional penalties." The former economist and first-term senator says he wants to cut off their access to representation in Congress, enshrined in the agreement, under which FARC transformed itself into a political party. Duque is buoyed by the backing of his popular mentor, former president and now senator Alvaro Uribe, whose two-term presidency from 2002-2010 was marked by all-out war on the FARC. Petro, 58, is the first leftist to reach a presidential runoff in Colombia, and believes his presence shows the South American country has shed its suspicions of the left, tainted by 50 years of conflict. A former member of the disbanded M-19 guerrilla group, he says he will implement the agreement with FARC, which has transformed itself into a political party amid a struggle to integrate its 7,000 ex-combatants into civilian life. Highlighting Colombias glaring inequalities during his campaign, Petro has said that if elected he will buy out land owned by the big agro-industrial companies and redistribute it to poor farmers. The latest polls show Duque, a candidate for Uribes Democratic Center party, would beat Petro by between six and 15 points on Sunday. "Undoubtedly, for the peace process, this is an important test," said Patricia Munoz, a professor of political science at the Pontifical Xavierian University in Bogota. In a sign of how tense relations between both camps of voters remain, even acts of nature have turned into fodder for political jousting. A week before the vote, a swarm of killer bees attacked supporters who showed up to see Uribe speak at a Duque rally in a small town in northern Colombia. Supporters of Duque accused Petro backers of launching the bees in an act of "biological terrorism." "Now African bees as Petristas," Petro groaned later on Twitter, using the play on his last name used to describe his supporters. "Is it because they are worker bees?" Officials later said Uribes helicopter had likely stirred the bees into a frenzy. Analysts say Petros candidacy is an important development in a country where more than five decades of conflict against rebels created a stigma around any candidate who appeared to sympathize with leftist causes. If he were to win, he would likely face an uphill battle in implementing any of his campaign proposals. His allies represent a minority in congress and would struggle to pass any laws. "The entire panorama today indicates the peace process is not reversible," Munoz said. "We have a society that does not want the FARC to return to armed conflict."