This video from the USA is called CIA Director Richard Helms on Ways to Kill Castro.
From British daily The Independent:
Ailing Cuban leader Fidel Castro said today that he will not return to lead the country, retiring as head of state 49 years after he seized power in an armed revolution.
Castro, 81, said in a statement to the country that he would not seek a new presidential term when the National Assembly meets on 24 February.
English translation of Castro’s letter is here.
See also here.