Venezuelan President Hugo Chavez has accused the United States of harbouring terrorists.
He used an Ibero-American forum in Spain to attack the US, increasing the anti-Washington flavour of the summit expected to back stronger criticism of Washington's embargo on Cuba.
Cuban President Fidel Castro, a veteran foe of the United States, stayed away from the summit but Mr Chavez made up for his absence by lambasting capitalism and US policies.
"[The United States], which says it fights terrorism, which invades countries like Iraq using the excuse of the war on terror ... protects terrorists on its own territory," Mr Chavez said as he was mobbed by reporters and flag-waving supporters at a Salamanca hotel.
He was referring to a former CIA operative Venezuela wants extradited over the 1976 bombing of a Cuban airliner. A US judge has ruled that Luis Posada Carriles, who has denied involvement in the bombing, may not be deported to Cuba or Venezuela, saying he faced the threat of torture.
Cuba put a controversial resolution before the summit supporting Mr Posada's extradition from the United States. Foreign ministers approved a general resolution on extraditing terrorists, but a Spanish government spokesman said the precise reference, sought by Cuba, to the Cubana de Aviacion bombing was left out.
The ministers also agreed on a resolution criticising the US trade embargo of communist Cuba in stronger language than used before, calling it a blockade instead of an embargo.
Cuban Foreign Minister Felipe Perez Roque has expressed Cuba's satisfaction over both resolutions, which must still be approved by leaders before the summit ends today.