Videos of 10 Colombian soldiers and police officers held by Marxist rebels for as long as 11 years aired on television on Monday, but efforts aimed at freeing the gaunt-looking hostages remained frozen.

The men are seen bound around the neck by chains secured by copper-colored padlocks. A tarp of camouflage material hanging behind them to hide their location, they speak directly to their families in the videos and plea for freedom.

Leftist Senator Piedad Córdoba has been authorized by the government to broker the hand-over of 24 high-profile hostages held in secret jungle camps by the Revolutionary Armed Forces of Colombia, or FARC, Latin America's oldest armed insurgency.

But the FARC and President Alvaro Uribe, a conservative US ally popular for cracking down on the guerrillas, are far apart on terms for a release.

Uribe insists that all 24 be freed at the same time, a condition the FARC calls impossible to meet. The rebels, labeled terrorists by Washington, say the hostages can be freed only in exchange for guerrillas held in government jails.

The tapes were recovered over the weekend from a FARC operative before he was arrested by authorities. The proof-of-life videos were filmed by the guerrillas to increase pressure on the government.

"I am in good health," police officer Jorge Trujillo says to the camera in one of the tapes, his beard specked with gray. His voice then trails off and he appears disoriented.

The plight of Colombian kidnap victims drew worldwide attention last year with the stunning military rescue of French-Colombian politician Ingrid Betancourt and three American anti-drug contractors held for more than five years.

The guerrillas finance their 45-year-old war against the state through cocaine smuggling and extortion. They kidnap for ransom and to increase their political leverage.

Uribe may run for a third four-year term next year if his supporters succeed in changing the constitution to allow him another campaign. His father was killed in a rebel kidnapping attempt in the 1980s.