Reyes demanded that Alvaro Uribe, the Colombian president, withdraw troops from a large area of the country before any negotiations begin.

"We continue seeking the demilitarisation of Pradera and Florida, and we would ask President Chavez to use his political weight to contribute to this, which would allow us to sit at the negotiating table and arrive at an accord to release the prisoners," Reyes told Argentine newspaper Clarin.

Relatives

Last week, the relatives of some of hostages held by the Farc appealed to Chavez to help broker a deal between the group and the Colombian government.

Farc has held hundreds of police, soldiers and politicians for years, including Ingrid Betancourt, a former Colombian presidential candidate seized in 2002.

Yolanda Pulecio, Betancourt's mother said after meeting Chavez: "I think it's the moment for Venezuela to help us." 

Chavez offered the relatives "all the help we can give" and said he was willing to hold talks with Manuel Marulanda, the Farc leader, or whoever else the rebels choose.

"Starting today we will begin to work to try to make contact with Farc high command ... so that we can start hearing positions. I have very, very much faith we will achieve that point of agreement," Chavez said last week.

The Venezuelan leader has long denied any US claims that he has aided Farc and has insisted on staying out of Colombia's internal conflict.

The left-wing group has been trying to overthrow the government for more than four decades.