Cuban leader Fidel Castro said on Wednesday he is not strong enough to speak in public more than 17 months after stomach surgery forced him to hand over power to his brother.

Castro's long illness he last appeared in public on July 26, 2006 has raised speculation about his possible retirement when Cuba's legislature, the National Assembly, sits in March.

I am not physically able to speak directly to the citizens of the municipality where I was nominated for our elections next Sunday, Castro said in a essay published by Cuba's state-run newspapers.

The 81-year-old leader looked frail but cheerful in photographs of a meeting he had on Tuesday with Brazilian President Luiz Inacio Lula da Silva.

Castro wore the tracksuit top he has used during his long convalescence, over his pajamas, and was seen standing in a corridor chatting with Lula. Another picture showed him playfully taking a photograph of the Brazilian president.

Lula said the Cuban leader was incredibly lucid and did most of the talking during the two-and-a-half-hour meeting, and was well enough to return to politics in Cuba.

Castro has only appeared in video and photographs since emergency intestinal surgery forced him to hand over power temporarily to his brother Raul Castro in July 2006.

In recent writings, though, he has hinted that he does not intend to cling to power, which he has held since a 1959 revolution that turned Cuba into a communist state.

To continue formally as Cuba's head of state, Castro must be a member of the National Assembly, and he has been nominated for one of its 614 seats on the slate of candidates for the eastern city of Santiago.

It is not clear whether Castro is well enough to continue as president of the executive Council of State or will be succeeded by his brother or another Cuban leader when the National Assembly approves the council's members in March.

The photographs of Lula's visit were the first pictures of Castro in almost three months, although he has maintained a public presence by writing regular columns and essays.

I do what I can: I write, he said in his latest essay, an indictment of U.S. President George W. Bush's visit to the Middle East.

For me, this is a new experience: writing is not the same as speaking, he wrote.