'Race against clock'
The calls come as Nicholas Sarkozy, the French president, made a plea for Betancourt's release and said he was prepared to travel to Colombia to fetch her himself.
"They cannot let this woman die. It is a race against the clock [and] we can wait no longer"
Nicholas Sarkozy, French president
"They cannot let this woman die. It is a race against the clock [and] we can wait no longer," he said on Thursday during a trip to South Africa.
"The Farc must know and understand that the martyrdom of Ingrid Betancourt is the martyrdom of France."
Hugo Chavez, the Venezuelan president who helped broker the hostage deal, also called on Manuel Marulanda, the Farc's leader, to move Betancourt to a safe location "urgently".
Juan Carlos Lecompte, Betancourt's husband, told Al Jazeera he and her family were asking France, the EU and the Venezuelan leader to aid her release.
"We have a lot of faith. A lot of hope that Mr Chavez can do something."
Luis Eladio Perez, a Colombian former senator and one of the four hostages released on Wednesday, said that Betancourt was being singled out for particularly inhumane treatment by her captors.
"She is being kept in inhuman conditions. She has been very badly treated by the guerrillas [and] the whole world needs to know that," he said following his release.
The former hostage also said the health of three US Pentagon contractors who have been held for five years, Thomas Howes, Marc Gonsalves and Keith Stansell was also declining.
The men, who were captured after their plane crashed in Farc-held territory, had written letters to George Bush and Democratic members of congress pleading for assistance, but the letters were confiscated by the Farc, Peres said.
The other three hostages released are Colombian politicians Gloria Polanco, Orlando Beltran, and Jorge Gechem, who was released on the grounds of his ill health.
Their release follow the freeing of two women hostages, fellow former Colombian lawmakers Clara Rojas and Consuelo Gonzalez, last month.
On Wednesday the Revolutionary Armed Forces of Colombia (Farc) repeated its demand for the creation of a demilitarised zone in order to negotiate a prisoner swap between remaining political hostages and about 500 Farc fighters being held in Colombian prisons.
|President Uribe has so far refused to create a |
demilitarised zone for negotiations [AFP]
Alvaro Uribe, the Colombian president, has indicated a willingness to negotiate an exchange of prisoners.
However, he has ruled out the demilitarisation of such a large and populated part of the country - suggesting a smaller zone instead.
On Thursday, Fabrice Delloye, Ingrid Betancourt's ex-husband and the father of her two children, called on world leaders to support Uribe and urge him to create such a zone.
"We [ask] heads of states around the whole world to give their support to Uribe so, in order to save the life of his fellow citizens ... he bravely accepts as soon as possible and with the help and support of the international community to discuss the conditions of a humanitarian agreement," he said.