The video is the first proof in more than a year that she is alive

Ingrid Betancourt delivered her message in a videotape which was broadcast by Colombian television.

It is the first indication in more than a year that Ms Betancourt is still alive.

She was last seen in a previous video released in July 2002.

The guerrillas, from the Revolutionary Armed Forces of Colombia (FARC), want a number of rebel prisoners released in exchange for Ms Betancourt.

There is no clue as to when the tape was made, although in it Ms Betancourt refers to an incident on 5 May 2003.

In the videotape, Ms Betancourt said Colombian President Alvaro Uribe should order a rescue mission.

"A rescue, yes, definitely, but not just any rescue.

"It's important that it be the president who directly makes this decision. I believe it is not a military decision, but a political one," she said.

Family plea

The exchange is the moral obligation of a democratic state Ingrid Betancourt

Ms Betancourt's family have urged President Uribe not to launch a rescue attempt after a French rescue mission went wrong and the FARC killed 10 other hostages.

The former senator appealed to the government to release some FARC prisoners.

"The exchange is the moral obligation of a democratic state," she said.

Ms Betancourt and her presidential campaign manager Clara Rojas were kidnapped by the FARC after they tried to cross into their territory.

It is not known if Ms Rojas is still alive.

She was last seen alongside Ms Betancourt in last year's video, which was apparently filmed in May 2002.

The latest video is believe to have been made after 5 May 2003, as Ms Betancourt referred to the deaths on that date of Medellin Governor Guillermo Gaviria and former defence minister Gilberto Echeverri.