BOGOTA (Reuters) - Colombian President Juan Manuel Santos was ahead of right-wing challenger Oscar Ivan Zuluaga in a presidential ballot on Sunday that may decide whether peace talks with Marxist FARC rebels continue and offer an end to five decades of war.

With 56 percent of the voting tables counted, center-right Santos had 51 percent versus 45 percent for right-wing economist Zuluaga.

(Reporting by Bogota newsroom)