Brazilian President Luiz Inacio Lula da Silva. AFP PHOTO

"I am a lover of the Cuban Revolution," Lula, his country's first democratically elected leftist, who has had fairly warm relations with Cuba, told the newspaper Folha de Sao Paulo in an uncharacteristic criticism.

"I only regret that Fidel Castro did not carry out a process of political opening while he was alive," Lula added, apparently misspeaking on the state of Castro's health.

Fidel Castro, 80, in July handed over the presidency temporarily for the first time in almost five decades to his brother Raul Castro, 75, while he recuperates from surgery. Fidel Castro, however, has not been seen in official Cuban media in a month.

"In my opinion, (Castro) could have taken Cuba on a great leap forward. He did not do it. Now Raul has taken over the interim presidency and I do not know what he will do, but I think that our (Cuban) comrades missed their chance to move closer to democracy," said Lula, a founder of the Workers Party.

Lula, a former union leader from a humble background, visited Cuba in September 2004.  Fidel Castro attended Lula's inauguration in January 2003.

Cuba is the Americas' only one-party communist regime.