Angered by the rebel's capture from its territory, Venezuela on Thursday recalled its ambassador from Bogota for consultations - a diplomatic form of expressing concern which stops short of an official protest.
Colombia, which has fought a four-decade-old war against the 17,000-strong leftist rebel group Farc (Revolutionary Armed Forces of Colombia), has said the rebel foreign relations chief Rodrigo Granda was arrested on its soil in December.
But in private, Colombian officials admit he was snatched in Caracas. The operation reportedly involved rogue Venezuelan soldiers paid by Colombia.
Washington and Bogota call the Farc a terrorist organisation and they have repeatedly asked Colombia's neighbours not to shelter its members.
Venezuelan Interior Minister Jesse Chacon said investigations so far showed two officers and three soldiers of the elite Venezuelan National Guard anti-kidnap squad carried out Granda's abduction in December.
"This was a violation of Venezuela's sovereignty which we reject," Chacon said.