Havana.– Cuba's communist strongman Fidel Castro turns 80 on Sunday, ailing and secluded but still making waves after temporarily ceding the power he held for almost 48 years in defiance of US attempts to oust him.

He has not been seen in public since announcing in a statement on July 31 that he had handed over authority to his brother Raul, but is once again in the limelight he cherishes amid speculation about his condition and the future of the western hemisphere's last communist nation.

The nemesis of 10 successive US presidents, Castro has survived assassination attempts, a failed invasion and a tough US economic embargo since he led the 1959 Cuban revolution.

But an intestinal ailment forced him to undergo surgery and cede power on July 31 to Raul, 75, his designated successor and defense minister.

Officials insist he is well on his way to recovery and will soon be back in the saddle, but say details of his health have to remain a state secret in view of what they call US attempts to destabilize the Caribbean nation.

Messages from well-wishers around the world have flooded in, and Havana streets are festooned with birthday banners for the bearded icon, some optimistically calling for "80 more years".

But Castro, in announcing the power transfer on July 31, also asked his birthday celebration be postponed to December 2, the 50th anniversary of when he landed a small boat filled with rebels in Cuba, launching the Cuban revolution.

A Jesuit-educated lawyer who came to power at the age of 32, Castro has been the perpetual thorn in the side of the US, which was alarmed and embarrassed by Castro's establishment of a Cold War Communist-bloc nation just 144km off its southeastern flank.

Following the revolution, he became an icon of international socialism, sending as many as 15,000 soldiers to help Soviet-backed troops in Angola in 1975, and dispatching forces to Ethiopia in 1977.

A driving force behind the Non-Aligned Movement – which will hold a summit in Havana next month – Castro has also drawn admiration among developing countries for demonstrating that a sovereign nation, however small, could thumb its nose at the mighty US and get away with it.

Known for his fiery and long-winded oratory, the tempestuous Cuban president, known on the island nation as "Fidel" and "the Commander," has maintained a reputation as a workaholic, micromanaging every aspect of life in Cuba, frequently addressing the nation and rarely missing a photo opportunity.

But his foes call him a brutal dictator who drove Cuba, once known as "the Pearl of the Caribbean," to the brink of economic ruin.

Born on August 13, 1926 to a prosperous Spanish immigrant landowner and a Cuban mother of humble background, Castro was a quick study and a promising baseball player who, as a youth, dreamed of playing in the US big leagues.

He studied law in Havana and later joined a failed coup in the Dominican Republic.

He was jailed in 1953 after leading a raid on the Moncada military barracks in the eastern Cuban city Santiago, in which dozens of his followers were killed.

After his release, he fled to Mexico, where he met the now iconic Argentine revolutionary Ernesto “Che” Guevara. On December 2, 1956 he returned to Cuba on the boat “Granma” and led a small band of fighters on another ill-fated attack, before finally driving pro-US dictator Fulgencio Batista into exile in 1959.

Castro, who recently joked he would probably live to be 100, has weathered numerous challenges, including the 12-day 1962 Cuban missile crisis, widely seen as the closest the Cold War ever got to escalating into a nuclear confrontation.