The Colombian government broadcast videos on Friday of kidnapped politician Ingrid Betancourt and three Americans in the first proof since 2003 that the high-profile rebel hostages were still alive.
The videos, which also showed Colombian military officers kidnapped by guerrillas, were confiscated from three suspected rebels captured in Bogota and included images from October, Peace Commissioner Luis Carlos Restrepo said.
Betancourt, a dual French-Colombian citizen and former presidential candidate captured in 2002, and the Americans are among the most well-known captives held by the Revolutionary Armed Forces of Colombia rebels waging Latin America's oldest insurgency.
In a Colombian army operation against the FARC's urban networks, three people were captured and in their possession was found proof of life of a group of kidnap victims, said Restrepo.
Brief clips of the videos broadcast by local television showed images of Betancourt sitting in jungle surroundings and the Americans. U.S. contractors Thomas Howes, Marc Gonsalves and Keith Stansell were snatched by the FARC when their aircraft crashed on a counter-narcotics mission.
Restrepo said photographs and letters from hostages were also found.
All we see is a single photo where she is sitting at a small table and appears fairly thin, with very, very long hair. She is looking down. I had the feeling that her hand was chained. It's a sad image of my sister, but she is alive, Betancourt's sister Astrid told LCI television in France.
French President Nicolas Sarkozy played a key role in recent efforts to broker a deal to free FARC hostages in exchange for jailed rebel fighters. Earlier this year, Colombian President Alvaro Uribe freed a FARC commander to try to broker talks and in August invited Venezuelan President Hugo Chavez to mediate.
Sarkozy said the findings were encouraging.
Now that we know she is alive, we must fight relentlessly to obtain her release and an end to this ordeal as quickly as possible, Sarkozy told reporters in Nice.
The FARC wants to exchange around 50 hostages for jailed rebels, but efforts by Chavez to broker a hostage deal fell apart after Colombia suspended his role as mediator.
Uribe said the Venezuelan leftist had broken with protocol by contacting a top Colombian military chief without permission.
The failed hostage release efforts triggered a diplomatic spat between Uribe and Chavez, who has said he will have no relations with Colombia while Uribe is in office.
Started in the 1960s as a leftist insurgency, the FARC is now deeply engaged in Colombia's cocaine trade and has kidnapped scores of police, soldiers, business owners and lawmakers for ransom and political leverage.
While violence from Colombia's 40-year-old conflict has ebbed under Uribe, the conservative leader is under pressure to resolve the plight of hostages still held in secret jungle camps, some for as long as nearly a decade.
Negotiations over the FARC hostages have been stalled over rebel demands Uribe demilitarize an area the size of New York City in southern Colombia as a condition for talks. The U.S. ally has refused such a safe haven under rebel terms saying it would allow the FARC to regroup.
(Additional reporting by Laure Bretton and Emmanuel Jarry in Paris; Editing by Doina Chiacu)