HAVANA (AP) — Colombia's main rebel group is appealing to U.S. President Barack Obama to free a guerrilla leader serving a long prison term in the United States.

The Revolutionary Armed Forces of Colombia says Simon Trinidad's presence at the current peace talks with the Colombia government in the Cuban capital of Havana would be an "immense" help to negotiations.

The FARC rebels named Trinidad to their negotiating team in September, even though he is serving a 60-year prison term. Last week, the rebels brought a life-sized cardboard cutout of Trinidad to a negotiating session. But American officials say it's unlikely any FARC rebels imprisoned in the US will be freed.

The rebels made the appeal to Obama on Friday. The FARC has waged war on the Colombian government for a half century.