Havana ? Ailing Fidel Castro was not well enough to attend the kickoff Tuesday of his 80th birthday celebrations, attended by hundreds of admirers who traveled here to fete him.

A government worker at the gala launch of the five-day birthday bash read a message that he said came from the Cuban leader. It said Castro’s doctors had told him he was not in condition to go to the party at Havana’s Karl Marx Theater.

“I direct myself to you, intellectuals and prestigious personalities of the world, with a dilemma,” said the note.

“I could not meet with you in a small locale, only in the Karl Marx Theater where all the visitors would fit and I was not yet in condition, according to the doctors, to face such a colossal encounter,” it added.

The crowd responded with a standing ovation.

“My very close friends who have done me the honor 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,” the message said.

The Cuban leader has been seen by the public only in photos and videos since his July 31 announcement that he was temporarily ceding power to his brother, 75-year-old Defense Minister Raul Castro, while he recovered from surgery for intestinal bleeding.

Details of his ailment and his medical treatment are state secrets, but U.S. officials believe he has terminal cancer of the stomach, colon or pancreas.

The festivities were originally scheduled around Castro’s actual birthday on Aug. 13. Castro asked to postpone them to Dec. 2 to coincide with the 50th anniversary of the founding of Cuba’s Revolutionary Armed Forces.