Cuba's President Raul Castro declared the global climate summit in Copenhagen a failure from the start and urged left-wing Latin American leaders to devise their own plan on how to cope with climate change.
Addressing a two-day meeting of the leftist Bolivarian Alternative for the Americas trade group, Mr Castro said that although Copenhagen should produce "concrete, verifiable steps to confront the effects of climate change, we already know there will be no agreement".
He said that instead, the world "can only wait for a political pronouncement".
Cuba has not sent any representatives to the global climate summit in Denmark, where world leaders hope this week to forge the framework of a plan to limit the causes of global warming.
Instead, Mr Castro implored leaders from the nine-country group gathered in Havana to devise their own "firm position on this decisive matter for the future of the human species".
The trade group was formed by Venezuelan president Hugo Chavez, a self-described socialist, as an alternative to US-backed free-trade consortiums. Its members are Venezuela, Cuba, Nicaragua, Honduras, Ecuador, Bolivia, Antigua and Barbuda, San Vincent and the Grenadines, and Dominica.
Mr Chavez responded harshly to comments made earlier in the week by US secretary of state Hillary Clinton, who warned Latin American nations to "think twice" about building ties with Iran.
Venezuela's president, who has travelled to Iran, said "Mrs Clinton's declarations (were) like a threat, more than anything against Venezuela and Bolivia but also against all" members of the trade bloc.
"She says, 'They should think twice'. It's an open threat."
Nicaraguan president Daniel Ortega and Bolivia's President Evo Morales also attended the meetings at a sprawling Havana convention centre.
Honduras remains part of the bloc despite a military coup that toppled President Manuel Zelaya in June.
Mr Zelaya's deposed foreign minister attended the meetings in Havana, but Honduras' interim government will almost certainly not abide by any agreements made.