San Antonio, Venezuela: More than two dozen Colombian prisoners arrested three years ago in an alleged plot against President Hugo Chavez were freed in a goodwill gesture he hopes will help facilitate a prisoner exchange in Colombia.

The 27 Colombians who boarded a bus on Saturday to return home after being pardoned by Chavez were among more than 100 men arrested three years ago on accusations of plotting to stage a rebellion and assassinate the Venezuelan leader.

In a speech in Caracas, Chavez said he expects to meet soon with a high-ranking representative of the Revolutionary Armed Forces of Colombia, or FARC, to arrange a possible exchange of hundreds imprisoned guerrillas for about 45 prominent rebel-held hostages.

Among those being held by the rebels are three US defence contractors and former presidential candidate Ingrid Betancourt, a French-Colombian citizen.

The Colombian government and FARC have voiced support in principle for the swap but have long argued about how to achieve it. Chavez acknowledged stepping into a difficult role, but said he hopes to eventually "move toward a peace accord in Colombia".

"Nothing is impossible when you put your heart into what you do," Chavez said. "If I had to go to the gates of hell to try achieve the humanitarian accord in Colombia, I'd be willing."