Fidel Castro is "battling for his life," Venezuelan President Hugo Chavez said Friday, marking a drastic change in tone from a close friend and ally on the ailing Cuban leader's condition. 

The fiery leftist leader told reporters that he spoke with Castro for nearly half an hour several days ago.

He compared Castro's attempt to recover from an unspecified medical condition to the 1950s, when Castro was a guerrilla in Cuba's eastern mountains fighting the government he would eventually overthrow.

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

Chavez said he could not give more details about Castro's condition "because I'm not the doctor who's caring for Fidel.

"And if I was, I wouldn't anyway, but nevertheless I can tell you: I don't know when Fidel will die, I hope he lives 80 more years, I hope he lives 100 more years."

In a speech Wednesday night, Chavez called Castro's situation "delicate" but dismissed as speculation recent Spanish press reports portraying Castro as near death after three failed operations and complications from the intestinal infection diverticulitis.

Castro's health a state secret

Cuba has released little information on Castro's condition since he temporarily ceded power in July 2006 to his brother, Defence Minister Raul Castro, until he could recover from emergency intestinal surgery, prompting much speculation and rumour in the country and around the world.

Cuban authorities have denied Castro suffers from terminal cancer — as U.S. intelligence officials have claimed — but have nonetheless stopped insisting he will return to power.

Cuban officials told visiting U.S. lawmakers in December that Castro did not have a terminal illness and would eventually return to public life, though it was uncertain whether he would resume total control of the country as before.

With files from the Associated Press