Associated Press
Photo released by the Colombian government on Friday shows former Colombian presidential candidate Ingrid Betancourt.

BOGOTA, Colombia — A former presidential candidate held by leftist rebels describes in an emotional letter how she has lost her hair, appetite and hope after nearly six years constantly on the move in Colombia's jungles.

The letter, along with videos released by government officials Friday, were the first evidence in years that Ingrid Betancourt and other rebel-held hostages, including three U.S. military contractors, may still be alive.

The materials were seized during the arrest in Bogota of three suspected members of the Revolutionary Armed Forces of Colombia, or FARC.

"Here, we are living like the dead," Betancourt writes to her mother. The dual French national was kidnapped in February 2002 while campaigning for the presidency.

An outspoken former lawmaker who was once determined to tackle Colombia's rampant corruption, Betancourt sounds resigned and weakened in the 12-page handwritten letter, which is dated Oct. 24. Excerpts were released to The Associated Press in Paris by people close to her family.

"I no longer have the same strength, it is very difficult for me to continue believing," she writes. "I am not well physically. ... My appetite is frozen, my hair is falling out in large quantities."

A short videotape released with the letter shows grainy images of an extremely gaunt Betancourt staring at the ground, rosary in hand.

Each of the three Northrop Grumman Corp. contractors, who have been held since their surveillance plane went down in February 2003 in rebel territory, also appear in videos.

In an interview with the left-wing Bolivarian press agency released Saturday, a FARC commander who calls himself "Ivan Marquez" said the group would not send more proof that the captives are alive anytime soon because it was too risky for the people delivering it.

"Bogota's folly forces the FARC to take drastic actions because it cannot run the risk that other emissaries will be detained," said Marquez, who is also known as Marin Arango.

On Saturday, Venezuelan President Hugo Chavez, who had been trying to broker a humanitarian exchange until Colombia's government canceled that role recently, said FARC chief Manuel "Sureshot" Marulanda has expressed willingness to free a group of hostages as part of talks with the Venezuelan leader.

"I sent word to Marulanda ... if I go there, I shouldn't come out with empty hands. My visit on its own is already a condition," Chavez said. "My visit there would have to be conditioned on the liberation of a first group of people, to begin with, and Marulanda accepted."

It was not clear whom the FARC might consider freeing from its 46 high-profile hostages.

In the letter, Betancourt describes stretching to relieve her sore neck, speaking as little as possible, and says it is a "problem" to be the only woman among several male prisoners, some of whom have been held for a decade.

Betancourt describes her joy in hearing her mother and other supporters send her messages through a jungle radio station. She appeals to her daughter and son, who live in France, to send three messages a week even though she can't respond. And she urges the children to get doctoral degrees.

"Life is not life here, but ... a gloomy waste of time," she writes. "I live, or subsist, on a hammock stretched between two stakes, covered with a mosquito net and with a tarp above, which works as a roof and allows me to think I have a house."

Some blamed President Alvaro Uribe, who has said he would prefer to rescue them in military operations.

Betancourt's letter expresses hope in mediation efforts by Chavez, President Nicolas Sarkozy of France and President Bush.

The U.S., French and Colombian governments had demanded evidence the captives were alive during Chavez's mediation effort to win the release of 46 high-profile hostages held by the FARC.

Although it now appears the FARC intended to eventually deliver the material, Uribe abruptly ended Chavez's mediation role on Nov. 21.

The rebel commander, Marquez, confirmed the videos and letters were destined for Chavez.

"The proofs were going to President Chavez, and the Colombian government knew it," he said, adding that Chavez "with all certainty was going to find a definite solution to the humanitarian drama of prisoners held by both sides."

Marquez added: "With Uribe acting this way, there will never be an exchange."

Uribe claimed Chavez had overstepped his bounds by directly contacting the head of Colombia's army.

On Saturday, Sarkozy spoke by telephone with Uribe and expressed concern about "the obvious precariousness" of Betancourt's health and "about her despair," his office said in a statement. He urged Uribe to act urgently to pursue a hostage swap.

Betancourt's mother, Yolanda Pulecio, told the AP that she did not want the letter released publicly. She said she had received it from the chief prosecutor's office and that its release "violated the family's intimacy."

"I ask Marulanda, I beg him: take advantage of this historic opportunity, make a humanitarian gesture, free those whom you have there, the women and children," Pulecio said in between sobs during an interview broadcast Saturday on state television in Venezuela.