Colombian Marxist rebels kept up pressure on the government to release imprisoned guerrillas, releasing a videotape of 12 former congressmen they kidnapped 30 months ago and want to swap for their comrades.

The former provincial congressmen, looking lean but in good health, called on President Alvaro Uribe to negotiate a deal to exchange them and another 60 hostages for jailed members of the Revolutionary Armed Forces of Colombia. The video was obtained by Reuters on Monday.

"The whole country now understands that the best way to resolve our tragedy is by negotiation. Public opinion supports this overwhelmingly," said the congressmen in a letter they read on the video, made in a hidden prison somewhere in the jungle.

The rebels, who are known by their Spanish initials FARC and who have been fighting the government for 40 years, are holding 72 high-profile hostages they want to swap for thousands of rebels in state prisons.

The prisoners include soldiers, former presidential candidate Ingrid Betancourt and three Defense Department contractors captured after their plane crashed in southern Colombia last year.

Uribe's government, which is popular because of its tough stance toward the guerrillas, has offered to free 50 guerrillas in return for the hostages. But a deal looks far away.

The former congressmen, kidnapped from a provincial Congress building in the city of Cali in April 2002 by rebels disguised as soldiers, sent mournful messages to their loved ones.

"I keep up the struggle because I love you. We'll meet again," said Juan Carlos Narvaez, in a message to his wife.

The 17,000-strong FARC is also holding hundreds of civilians for ransom.

The FARC, a 1960s-era peasant army that says it is fighting for socialist reforms, frequently releases homemade videotapes that carry the FARC seal -- an AK-47 assault rifle and a machete against the backdrop of a Colombian flag.

Last year, they released tapes of Betancourt and of the Americans, who warned they will be killed if there is a rescue attempt.