RIO DE JANEIRO, Brazil - Venezuelan President Hugo Chavez said Friday that Fidel Castro is "battling for his life" and said he spoke with the Cuban leader for nearly half an hour several days ago.

Chavez, a close ally an admirer of Castro, compared Castro's attempt to recover from an unspecified medical condition to efforts in the 1950s, when Castro was a guerrilla in Cuba's eastern mountains fighting the government he would overthrow.

"Fidel is in the Sierra Maestra again, battling for his life," Chavez said after attending a summit of South American leaders in Rio.

Castro, 80, has not been seen in public since shortly before July 31 when he announced he was temporarily stepping aside while he recovered from an operation.

He has provisionally ceded power to his brother Raul, the 75-year-old defense minister.

Castro's medical condition is a state secret, but Cuban authorities deny he suffers from terminal cancer, as U.S. intelligence officials have claimed. Cuban officials have nonetheless stopped insisting Castro will return to power.