Gunmen have killed a candidate for mayor in a central Colombian town, raising the number of political candidates killed ahead of this month's elections to 16.

Police said Jorge Roa and a companion were shot while driving near the town of Chivor, about 80 kilometers north of Bogota. Authorities did not immediately name any suspects in the incident.

Local media reported the family of the Conservative Party candidate had received threats from suspected rebels.

Authorities have blamed FARC rebels for most of the attacks in the campaign.