By Peter Murphy
CARTAGENA, May 16 (Reuters) - Colombia's right-wing presidential candidate Oscar Ivan Zuluaga is edging ahead of President Juan Manuel Santos in three voter polls after a survey published on Friday also showed Santos's recently comfortable lead has evaporated nine days before elections.
But the poll was conducted before Friday's announcement that the government had reached a deal with Marxist FARC guerrillas on ending the illegal drug trade. That key advance in peace talks that Santos started with the rebels in 2012 could prop up his support from those eager to see a peace deal.
The FARC and their smaller counterpart, the ELN, also announced a week-long ceasefire on Friday for the elections. Though in talks with the government in Cuba, the FARC are still in combat with government forces at home in Colombia.
Pollster Ipsos Napoleon Franco said Zuluaga, a former finance minister who is skeptical of the peace talks and would impose tougher conditions to continue them, would receive 29.5 percent of first round votes versus 28.5 for Santos. The Ipsos poll was published on the website of broadcaster RCN.
It said both candidates would receive 32 percent of the vote in a run-off ballot in mid-June, which now looks inevitable with both candidates far from the 50 percent needed to secure victory in the first round of the election on May 25.
Two other surveys on Thursday, by pollsters Gallup and by Cifras y Conceptos, also put Zuluaga slightly ahead, but the narrow leads in each, within the surveys' margin of error, technically mean they are tying in the polls.
Santos and Zuluaga differ little on economic issues, both favor investor-friendly policies, so the choice for many voters is likely to come down to their stances on the peace negotiations with Marxist FARC rebels.
While many Colombians have never known peace in their lifetimes and back the talks, some are fearful of the rebels gaining a foothold in politics through a peace deal and that its members will face little or no punishment for years of murder and abduction. The conflict has killed more than 200,000 people.
None of the other candidates in the race would be a direct threat to either Santos or Zuluaga in the first round, with former Bogota mayor Enrique Penalosa in third-place. He was ahead of Zuluaga in one April poll, but has slipped to 9.4 percent.
The number who would make a blank or protest vote, choosing no candidate, was 12.8 percent in Ipsos' survey, much higher than the 5.9 percent in a Gallup poll on Thursday.
The Ipsos poll of 1,799 people was carried out from May 13 to 15 and has a 2.3 percent margin of error. Santos had gained 5.5 percent more support than Ipsos' April poll while Zuluaga's previous 15 percent support had almost doubled. (Editing by Matt Driskill)