The Colombian government has released a high-ranking Revolutionary Armed Forces of Colombia (Farc) leader in a possible prelude to freedom for a prominent hostage held by the guerrillas.
Rodrigo Granda, the group's foreign minister, was released from prison on Monday after meeting the president's peace negotiator in the capital, Bogota.
More jailed fighters are expected to be released later this week to secure the freedom of 60 hostages, including three Americans, held by Farc.
Unconfirmed reports say Granda will be flown to Paris to present evidence that Ingrid Betancourt, a French hostage, is still alive, Al Jazeera reported.
"The government has given him all the guarantees so he can act as a facilitator to work for peace"
Alvaro Uribe, Colombian president
Granda was arrested in December 2004 after being snatched by police agents in Caracas in an operation that fuelled tensions between Venezuela and Colombia.
Alvaro Uribe, the president, said in a late-night television address: "Today after midday, Rodrigo Granda was freed from prison.
"The government has given him all the guarantees so he can act as a facilitator to work for peace."
Granda's release is part of Uribe's plans to free about 180 jailed rebels in a unilateral gesture he hopes will prompt Farc to release its hostages.
The Farc on Sunday rejected the president's plan and reiterated a demand he cede a demilitarised zone as a condition for talks.
Granda, dressed in street clothes and carrying a rucksack, was escorted from the maximum security prison in La Dorada, northeast of the capital, on to a helicopter, footage broadcast by the country's two main television networks showed.
Sandra Acosta, of the Roman Catholic Episcopate press office, said Granda is expected to travel to the church's headquarters in Bogota.
Miguel Gonzalez, Granda's lawyer, said: "Rodrigo Granda today obtained his precarious liberty ... in an unprecedented legal process and with the use of mechanisms that violate the constitutional and legal order."