A Colombian FARC rebel has offered to release French-Colombian hostage Ingrid Betancourt and other guerrilla captives in exchange for protection from extradition, President Alvaro Uribe said on Friday.

Efforts to negotiate with the FARC over its hostages, who have been held for as long as a decade in jungle camps, are stalled.

But the rebels have been weakened by recent deaths of three commanders and desertions fueled by government bounties.

Uribe said Colombia's intelligence agency, DAS, has responded by offering the guerrilla protection from extradition should the hostages be freed by the Revolutionary Armed Forces of Colombia, or FARC. But he gave few details or names.

"We sent a note to the guerrilla who offered to hand over Ingrid Betancourt and other kidnap victims," he said. "The DAS director send it with my authorisation, saying there will be no extradition if this goes through. We hope this is true."

Betancourt, a former presidential candidate, was kidnapped more than five years ago while campaigning.

She is the FARC hostage with the highest profile. Others include three US defence contractors kidnapped in 2003.

Uribe's announcement may signal a bid by FARC members to break away and surrender with hostages as the rebels struggle to remain united and come under more pressure from the military.

But some analysts questioned why Uribe would make public such a delicate negotiation.

"It seems contradictory, announcing this makes it less likely to happen," said Pablo Casas at the Security and Democracy think tank in Bogota.

"If there is a FARC front holding Betancourt, everyone in the FARC knows which front that is, and they would take countersecurity measures."

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