The meeting tentatively planned for October 8 in Caracas between Venezuelan President Hugo Chavez and representatives of leftist Colombian rebels has been postponed, Colombian Senator Piedad Cordoba said Wednesday in Washington, according to DPA. Cordoba is a mediator in talks between the Colombian government and the Revolutionary Armed Forces of Colombia (FARC) towards a humanitarian exchange of hostages held by FARC for imprisoned rebels. Chavez himself had hinted Tuesday that a postponement might be necessary. In comments to Venezuelan state television, Chavez stressed however that talks are "dynamic" and that French President Nicolas Sarkozy would shortly send a representative to Caracas to spur on the negotiations. Left-wing populist Chavez got involved in the process with the approval of conservative Colombian President Alvaro Uribe, and has been active in his role as mediator. FARC is holding captive more than 50 politicians and soldiers - including former presidential candidate Ingrid Betancourt, a French- Colombian citizen. They hope to exchange the captives for rebels held in prison, including two who have been extradited to the United States. In Bogota, Uribe told US Defence Secretary Robert Gates on Wednesday that he would not agree to a potential arrangement between the US and FARC for the return of two rebel leaders - known with the aliases "Simon Trinidad" and "Sonia" - who were extradited to the US on drug trafficking charges.