"Colombia awaits clarification of the statement to ensure such actions do not affect relations," it said.
US and European officials brand Farc as a terrorist group engaged in Colombia's cocaine trade.
The rebels are holding scores of hostages for ransom and political leverage.
Alvaro Uribe, the Colombia president and Washington's major ally in the region, is also engaged in a diplomatic spat with Venezuela over his decision to suspend Hugo Chavez's attempts to broker a hostage deal.
Ortega is an ally of the Venezuelan president.
Other Latin American countries and France have backed efforts to reach a deal to free hostages including Ingrid Betancourt, a former presidential candidate held since 2002.
Elsewhere on Friday former Colombian paramilitaries and victims of their violence destroyed a huge cache of weapons in a ceremony.
Foreign dignitaries, dozens of demobilised fighters and victims of their crimes dumped 18,051 rifles, machine guns and rocket launchers into a giant cauldron.
The arsenal, which included 2.7 million bullets and was handed over as part of a 2003 peace pact, was smelted into material that will be used to create metal sculptures to be auctioned off to compensate victims.
Ballistic evidence was collected from each weapon before its destruction, to assist special prosecutors investigating paramilitary crimes.
The peace accord with the United Self-Defense Forces of Colombia, a paramilitary umbrella group known as the AUC, led warlords to demobilise 31,000 men and confess crimes in exchange for reduced prison terms and protection from extradition.
|Over 18,000 rifles were destroyed [AFP]|