The Venezuelan consulate in Miami closed amid a political scandal this year, and now some 26,000 Venezuelans living in Florida must travel more than 650 miles to cast ballots.
FARC's move to put Timoleon Jimenez, also known as 'Timochenko,' in charge could prove a major obstacle to Colombia's hopes for a peaceful resolution to the conflict.
Venezuela withdrew its ambassador this week after Peru offered asylum to Chávez's political rival who faces corruption charges.
Manuel Rosales, who ran against Chávez in 2006, is seeking asylum in Peru.
President Medvedev visits Venezuela this week as a Russian nuclear warship leads joint maneuvers.