President Raúl Castro also called upon to allow independent monitoring of the country's human rights situation by UN experts and other human rights groups.
Sara López, Joaquín Aguilar and Guadalupe Borja have been detained since July 2009 for their activities as members of a group fighting high tariffs in Campeche.
Amnesty International has adopted its 55th prisoner of conscience in Cuba and urged President Raúl Castro to release him immediately and unconditionally.
Amnesty International has urged President Raúl Castro to release all prisoners of conscience after Orlando Zapata Tamayo died in Havana on Monday.
An Amnesty International delegation in Honduras monitoring the human rights situation around the presidential elections, has seen evidence suggesting an increased risk of excessive force by security forces.