French demand Betancourt release

Marchers were encouraged to wear white for the "marches blanches"

Marches have been held in France to call for the release of Ingrid Betancourt, a French-Colombian politician kidnapped six years ago.

She is being held by Colombian Farc rebels and is said to be seriously ill.

France's foreign minister, the human rights minister and the president's wife, were joined by the Argentine president for the Paris march.

Foreign Minister Bernard Kouchner said his country would not stop working for Ms Betancourt's release.

Medical mission

Several thousand people joined the politicians for the march in central Paris.

"We are not going to stop, we will never stop" the efforts to free Ms Betancourt, said Mr Kouchner.

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

A joint French-Swiss-Spanish medical mission has been in Bogota since Thursday to treat the 46-year-old Betancourt, if the Farc gives permission.

Mr Kouchner said he was waiting for word from the Farc for the medical team to proceed.

Lorenzo Delloye, Ms Betancourt's son, said earlier this week she had Hepatitis B and urgently needed a blood transfusion to stay alive.

The Colombian government has promised to suspend military operations against the Farc in the area where many of its hostages are believed to be held.

Ms Betancourt - a former Colombian presidential candidate - was pictured looking thin and frail in a recent video.

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

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