Cuban President Raul Castro says the country will not return to the Organization of American States (OAS) in a show of solidarity with Venezuela.
OAS Secretary General Luis Almargo has called for sanctions against Venezuela.
At a summit of Caribbean countries in Havana, Mr Castro called the OAS "an instrument of imperialist domination".
Meanwhile, former Spanish Prime Minister Jose Luis Rodriguez Zapatero has met jailed Venezuelan opposition leader Leopoldo Lopez.
It was Leopoldo Lopez's first visit from anyone other than family members or lawyers since the 45-year-old was sentenced to 14 years in prison last year after being found guilty of inciting violence.
Firm solidarity'
Cuba was expelled from the OAS in 1962 but following a recent thaw in relations with the US it was suggested that the island might return.
But Mr Castro appeared to rule out the possibility, offering "our most firm solidarity to our brothers the Venezuelan people, to the legitimate government of President Nicolas Maduro".