Photo released by Colombian government on 30 Nov 2007 shows former presidential candidate Ingrid Betancourt in unknown location

A former presidential candidate held by leftist rebels in Colombia says she no longer has the same strength and struggles to keep hope after nearly six years in secret rebel camps.

In a letter released by her family Saturday, French-Colombian hostage Ingrid Betancourt says she is the only woman among several male captives. She writes that she is not well physically, and says she is losing her hair and appetite.

Colombian officials seized the letter, along with videos of rebel-held hostages, during an arrest Thursday of three suspected members of the Revolutionary Armed Forces of Colombia, or FARC.

Officials say the images had a time stamp of October 24th and indicate the captives may still be alive.

Colombian President Alvaro Uribe says the images indicate that Betancourt, who was kidnapped by the FARC in 2002, has been subjected to torture.

In the grainy video, a long-haired Betancourt appears gaunt and sad, staring blankly at the ground. No images of her had been seen since 2003.

The videos of Betancourt and other captives were released days after Mr. Uribe ended Venezuelan President Hugo Chavez's role as mediator in talks to swap prisoners for hostages held by the rebels. Mr. Chavez responded by cutting diplomatic relations with Colombia.

The hostages' families have welcomed the latest development but expressed frustration at the lack of progress toward the release of their loved ones.

Some information for this report was provided by AP and Reuters.