Colombia's president said Tuesday he had approved a French mission to try to meet with hostages held by leftist rebels, including gravely ill politician Ingrid Betancourt.

The mission would be "to protect the deteriorating health of the hostages," President Alvaro Uribe said.

Betancourt, who holds both French and Colombian nationality, is being held along with dozens of other hostages by the Revolutionary Armed Forces of Colombia or FARC.

In Paris, French President Nicolas Sarkozy said he had called Uribe to inform him France was sending a humanitarian mission "without delay to contact the FARC and obtain access to our compatriot," his office said.

Uribe said once Colombia's military has the co-ordinates of the location for any meeting between the French delegation and the rebels, it will temporarily suspend military operations in the zone.

Earlier Tuesday, Sarkozy implored the rebels in a televised message to free Betancourt, whom he said was in danger of dying. Betancourt, who has spent six years in captivity, is said to be suffering from Hepatitis B and a skin disease.

In a televised message to rebel leader Manuel Marulanda, Sarkozy said the latest information about the health of Betancourt is "profoundly alarming."

"Ingrid is in danger of imminent death," Sarkozy said. "Since only a decision from you to save this woman from death is needed … Take this decision. Free Ingrid Betancourt."

The rebels want to swap Betancourt, 46, and dozens of other hostages, including three U.S. defence contractors, for all FARC rebels imprisoned in Colombia and the United States.