Among those in attendance for Monday's release was Rigoberta Menchu, the Guatemalan rights activist who won the 1992 Nobel Peace prize.
She said it is now time for Colombia's government to respond to the FARC's gesture with its own display of political willingness to attain peace.
But analysts caution that peace talks, even back-channel negotiations, could be a long time coming.
Many don't believe they could happen before 2014 presidential elections.
Vivian Sequera in Bogota, Colombia, and Frank Bajak in Lima, Peru, contributed to this report.
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