The daughter of kidnapped Franco-Colombian politician Ingrid Betancourt told the French premier Tuesday that she believed his government had not done its utmost to free her mother.

Melanie Delloye called in to a radio program where Prime Minister Dominique de Villepin was speaking. Her mother, a dual French-Colombian citizen, has been held by the Revolutionary Armed Forces of Colombia, or FARC, for five years.

"I think you have not used all the means at your disposal," Delloye told him, saying she especially wanted France to ask the United States to put pressure on Colombia to secure her mother's release.

Villepin replied that France was doing a lot of work behind the scenes and spoke of the difficulty of getting responses about the case.

"The reality of things is not exactly what you are describing," Villepin said. "We are doing it discreetly, out of concern for being effective, and we are doing it most often, unfortunately, with nobody listening on the other end."

FARC rebels kidnapped Betancourt while she was campaigning for Colombia's presidency on Feb. 23, 2002.

French Foreign Minister Philippe Douste-Blazy visited Colombia early last year to work on a stalled plan to free Betancourt and about 60 other hostages in exchange for the release of jailed rebels.