Colombia's main rebel group has rejected a French-led medical mission to treat hostages held by their fighters, including Ingrid Betancourt, a French-Colombian former presidential candidate held for more than six years.
The Farc said on Tuesday they had refused to allow the mission as France had not co-ordinated with them over it.
"We don't respond to blackmail nor media campaigns," the rebels said in a statement issued through the Bolivarian News Agency.
The move came a day after a French government plane arrived in Bogota, carrying doctors and diplomats who had hoped at least to see Betancourt.
The French mission was "the result of the bad faith of Uribe [the Colombian president] before the [French] government and heartlessly mocks the expectation of the relatives of the prisoners," the group said.
Concerns for Betancourt's welfare have increased since hostages who spent time with her and were recently released said that she was depressed and suffering from hepatitis B.
The Farc (Revolutionary Armed Forces of Colombia) snatched Betancourt in February 2002 as she campaigned for the Colombian presidency.
|The Farc has carried out a 40-year|
war against the government [GALLO\GETTY]
The Colombian government has offered an amnesty to Farc fighters as part of a deal to release the hostages, although the Farc is yet to respond to the offer.
The statement said the rebels had released six hostages earlier this year as a "gesture of generosity and political will" and called again on the Colombian government to set up a demilitarised zone where imprisoned rebels could be swapped for hostages.
The four-point statement, dated Tuesday, added that the Farc leadership "deeply" lamented that while they were working "in the direction of a prisoner swap".
Uribe instead was "planning and executing the "assassination of commander Raul Reyes".
Colombian forces killed Reyes in an attack on a rebel camp in Ecuador on March 1 that sparked a regional diplomatic crisis.
The Farc is holding hundreds of other Colombian hostages as part of what it has said is a Marxist armed struggle against the Colombian government.