There was no sign of a convalescing Fidel Castro as hundreds of thousands of Cubans marched through Revolution Plaza yesterday to celebrate May Day, an event the island's "maximum leader" had attended for decades without fail.

In a speech just before the huge annual parade began, Salvador Valdes, secretary-general of Cuba's central workers union, hinted it was highly unlikely the 80-year-old Castro would make his first public appearance since stepping down from power nine months ago.

"A speedy recovery and lots of health, dear Fidel," said Valdes, adding "Viva Fidel!" as the crowd shouted back "Viva!"

The place where Castro would have watched the festivities - a raised platform under a towering statue of Cuban colonial independence hero Jose Marti staring out over the plaza - was instead occupied by his brother Raul.

The acting president and defense minister, five years younger than his more-famous sibling, stood stiffly and smiled, occasionally waving as marchers streamed past, waving plastic Cuban flags, portraits of Fidel Castro and banners denouncing US "imperialism."

Special guests surrounded the base of the platform, including a Cuba solidarity group from the New York City area and a contingent of Brazilian union members.

In the hours before the march began, Fidel Castro issued the latest in a series of new communiques he has been writing in recent weeks - but gave no hint he would show up in public.

Castro called for a revolution in energy production in his latest message and reiterated his opposition to US plans to use food crops to produce ethanol for cars, predicting that American fuel needs would require the labor of the world's impoverished sugar cane workers.

"Tomorrow the 1st of May is a good day to carry these reflections to the workers and all of the poor people of the world," Fidel Castro wrote in the statement dated Monday evening.

On Sunday, one of Castro's main allies, Venezuelan President Hugo Chavez, said the Cuban leader is once again "in charge" but declined to comment on whether his friend would show for May Day.

Many marchers wore red or white T-shirts with a May 1 slogan reading "More solidarity, unity and strength than ever."

"There's hope in Latin America for a shift to the left," said Fredy Franco, a labor activist who was visiting from Nicaragua. "That's why we are here, supporting Cuba's socialist project."

Smaller marches were held simultaneously in cities around the island, with the government expecting several million people to participate.

Those gathered protested the recent decision to free on bond militant Luis Posada Carriles, pending his trial on US immigration charges. Havana accuses the Cuban-born Posada of orchestrating a 1976 airliner bombing that killed 73 people - a charge he denies.

Demonstrators held signs and banners declaring "Prison for the Executioner" in reference to Posada, accusing the administration of US President George W. Bush of a double standard on terrorism.

(Xinhua News Agency May 2, 2007)