Bogotá, May 26 (RHC) – President Juan Manuel Santos and ultra-conservative Oscar Zuluaga will compete in a run-off vote following Colombia's presidential election Sunday, with peace talks with FARC rebels in Havana as the central issue.

Far-right Zuluaga earned 29 percent of the vote against 26 percent for the president, according to official results. Since neither won more than 50 percent there will be a second round of voting on June 15th.

After the results Santos presented the election as a referendum on his center-right government's 18-month negotiations in Cuba with the Revolutionary Armed Forces of Colombia (FARC) guerrillas.

The runoff would be a choice "between those who want an end to the war and those who prefer a war without end," Santos told supporters in Bogotá.

Zuluaga, a former finance minister supported by hard-line former president Alvaro Uribe, threatened to end the talks instead.

Once ahead in opinion polls, Santos slipped as the campaign descended into a morass of mudslinging on both sides that included charges of espionage and corruption.

Santos and Zuluaga headed a field of five candidates, with conservative Marta Lucia Ramirez in third place with 15.5 percent.

The actual voting on Sunday took place with no problems. Defense Minister Juan Carlos Pinzon said it was the "safest election day in recent history" -- likely because the FARC had called a unilateral ceasefire during the vote.