HAVANA - Fidel Castro said Sunday that the US government continues to be a "killing machine" after revelations that nearly 50 years ago it tried to use American mobsters to kill him with poison pills.

Fidel Castro exhales cigar smoke in this March 1985 file photo during an interview in Havana. [AP]

"The empire has created a real killing machine made up not only of the CIA and its methods," the Cuban leader wrote in the latest of his nearly daily essays, published Sunday in the Juventud Rebelde.

President Bush "has constructed powerful and expensive superstructures of intelligence ... that lead to war, injustice, hunger and death everywhere on the planet," Castro wrote.

CIA documents made public last week described the agency's recruitment of a former FBI agent in August 1960 to use mobsters and poison pills to kill Castro. Information about the plot was among hundreds of pages of CIA internal reports, known as "the family jewels."

The plan was scrapped after the failed CIA-sponsored Bay of Pigs invasion of Cuba in April 1961, and US authorities retrieved the poison pills.

The 80-year-old Castro has not been seen in public in almost a year since handing power to a provisional government headed by his younger brother while he recovers from intestinal surgery.

Communist Cuba's parliament on Friday unanimously approved a resolution saying that the 47-year-old plot to assassinate Castro still reflects the reality of US policy toward the island.

"The conduct of the Bush government clearly shows its intention to keep employing the worst possible tactics against Cuba," it declared.

US law has forbidden official assassination attempts since the administration of Gerald Ford in the mid-1970s, and Washington denies it has tried to kill Castro since then.