Mission launched for Betancourt

Ingrid Betancourt's son told reporters his mother needed urgent treatment

France, Spain and Switzerland have launched a humanitarian mission to bring medical aid to a sick hostage held by rebels in Colombia.

Colombian hostage Ingrid Betancourt needs a blood transfusion within hours to stay alive, according to her son.

Lorenzo Delloye said his mother, who is also a French national, has hepatitis B and a skin disease that require a transfusion "in the coming hours".

A French plane carrying the mission landed in Colombia before dawn.

French Foreign Minister Bernard Kouchner said: "We have high hopes. We have done all we humanly could and now we need to wait for our envoys, the doctor, to reach the field."

There has been no word from Farc that they will allow access to Ms Betancourt, who was captured by left-wing rebel group in 2002 while campaigning for the Colombian presidency.

'In danger'

French President Nicolas Sarkozy announced the mission after Colombia agreed to suspend military operations against the rebels.

"A humanitarian mission of three facilitator countries, Spain, France and Switzerland, has started, in liaison with concerned authorities," a statement from the French president's office said.

INGRID BETANCOURT Born on 25 December 1961 Grows up in Paris 1989: Returns to Colombia 1994: Elected to lower house 1998: Becomes a senator 2002: Kidnapped by Farc rebels Profile: Ingrid Betancourt

Mr Sarkozy said Ms Betancourt was "in danger of imminent death".

Mr Delloye made an 11th-hour appeal at a news conference in Paris on Wednesday.

"This is my last appeal. There's no more time. Either we free mom and the other hostages or we'll lose them, and that's a question of hours," he was quoted as saying by Associated Press (AP).

Colombia's President Alvaro Uribe said the French mission, accompanied by the International Committee of the Red Cross, had his full backing.

"We have expressed our complete agreement to allow this international medical mission to make contact with the hostages and treat them," he said.

The BBC's Jeremy McDermott reports from Colombia that there is as yet no indication from Farc that they are ready to give up their most high-profile hostage.

'Grave blow'

He says that the recent killing of the group's chief negotiator was described by the rebels as a "grave blow".

Last week France offered to take in Farc rebels released from prison in exchange for 46-year-old Ms Betancourt, who has been held in the jungle since she was seized.

She was pictured looking thin and frail in a recent video.

Her case has drawn broad international attention for years, particularly in France, where she holds nationality acquired through her marriage to a Frenchman.

Her former husband has said he fears she may be dying or already dead.

She is one of 39 high-profile hostages whom Farc would like to exchange for 500 rebels currently in prison.

The rebel group has been fighting the Colombian government for over 40 years.