Cuban leader Fidel Castro knew that President John F. Kennedy was about to be assassinated by Lee Harvey Oswald in 1963,a former CIA agent has claimed in his new book. Castro was clearly aware that Oswald had told staff at the Cuban Embassy in Mexico City that he was going to murder the then US President Kennedy to prove his allegiance to communist cause,according to author Brian Latell,the United States spy agencys former chief intelligence officer for Latin America. In fact,on the morning of November 22,1963,the day Kennedy was killed,Castro had ordered a senior intelligence officer in Havana to stop listening for non-specific CIA radio communications and concentrate instead on any little detail,any small detail from Texas,Latell claims in his new book. Four hours later,the airwaves came alive with news that Kennedy was dead,says the book,titled Castros Secrets the CIA and Cubas Intelligence Machine,which is to set be released next month,the Daily Mail online reported. The author has based his book on interviews with former Cuban spies,backed up by declassified US government papers.