Fidel Castro: A "pure miracle" Obama has not been assassinated.

Mr Castro also accused American society of being marked by "profound racism", as he revealed his thoughts on the race for the White House ahead of the election on November 4.

He wrote: "Millions of whites cannot reconcile in their minds with the idea that a black man with his wife and children would move into the White House, which is called just like that - White".

He added that it was a "pure miracle" the Illinois senator, who became the first black politician to win the Democratic Party's presidential nomination, has not been the target of an assassination attempt.

The ailing Cuban communist leader described Mr Obama as a politician who "has the habit of looking at his opponent with serenity and laughing at his rhetorical attacks."

Mr Castro also mocked Republican candidate John McCain for his apparent poor grades at a naval academy and said the party's vice presidential nominee Sarah Palin "knew nothing at all about anything".

Mr Castro, who handed power to his brother Raul earlier this year, made his remarks in a commentary that appeared on the website Cubadebate.

His comments came as the White House race was hit by a war of words.

Civil rights icon John Lewis has accused Mr McCain of sowing "hatred" against Mr Obama, who is developing a strong lead in opinion polls. Mr McCain called the claims "shocking and beyond the pale".