Sick Castro misses his own postponed 80th birthday party

Fresh doubts have been raised about the health of Cuban leader, Fidel Castro, who said he was too unwell to attend the start of a week of celebrations to mark his 80th birthday.

In a message read to thousands of people gathered at the Karl Marx Theatre in Havana and broadcast on state television, Mr Castro said he had been advised not to attend by his doctors.

"I direct myself to you, intellectuals and prestigious personalities of the world, with a dilemma," said his message. "I could not meet with you in a small locale, only in the Karl Marx Theatre where all the visitors would fit, and I was not yet in condition, according to the doctors, to face such a colossal encounter."

Mr Castro turned 80 on 13 August this year but planned celebrations were postponed after he was forced to undergo intestinal surgery two weeks before his birthday. At the time he announced he was temporarily ceding many of his responsibilities as leader to his brother, Raul, his anointed successor.

As a result it was decided to merge the birthday celebrations with events planned to mark the 50th anniversary of the date that he, his brother and others first landed by boat on the in Cuba to launch the Cuban revolution. The boat ­ Granma ­ is on exhibit at the city's main museum.

A number of world leaders and celebrities have been scheduled to attend the celebrations, among them President Evo Morales of Bolivia and René Preval of Haiti. The Argentine football legend Diego Maradona, the South African singer Miriam Makeba and the Colombian novelist Gabriel Garcia Marquez are also due to attend.

Whether Mr Castro ­ who has not been seen in public since his operation was announced this summer ­ himself intends to play any part in the celebrations remains unclear.

In his message read out on Tuesday, he said: "My very close friends, who have done me the honour of visiting our country, I sign off with the great pain of not having been able to personally give thanks and hugs to each and every one of you."

When it was announced that Mr Castro had required surgery, it was also made clear that his precise ailment was considered a state secret and would not be made public. The state newspaper, also named Granma, reported that shortly after the operation Mr Castro had been able to walk about.

The report likened him to a tropical hardwood tree ­ the Caguairan ­ that is native to eastern Cuba and said: "A friend tells us that just a few hours ago, upon visiting the Comandante who was briefly dispatching some business, he witnessed some good news that he enthusiastically summed up in one sentence 'The Caguairan has risen'."

But since then a number of unidentified US officials have been quoted saying they believe the Cuban leader is suffering from an inoperable form of cancer, though no evidence has been offered to substantiate such a claim.

Shortly before Mr Castro turned 80, the Bush administration's Commission for Assistance to a Free Cuba issued a report outlining US plans to bring about "transition from repressive control to freedom" in Cuba.

The report said that $80m (£41m) would be spent over the next two years to "encourage and support Cubans who want change by providing uncensored information through conventional and satellite broadcasts, the internet and by strengthening democratic movements".

Critics of the US policy say it is at least partly driven by a wish to secure the support of the Cuban-American community in Florida, which remains electorally important. The Bush administration has tightened the US embargo against Cuba, making it more difficult for both Cuban Americans to visit family and all but impossible for ordinary US citizens to visit the island legally.