JFK Files: The CIA Planned To Assassinate Cuba's Fidel Castro With Exploding Seashell

Cuban revolutionary Fidel Castro during an address in Cuba after U.S.-backed President Fulgencio Batista was forced to flee. Keystone/Getty

New documents reveal the CIA wanted to conceal explosives inside a sea shell to assassinate former Cuban leader Fidel Castro.

The plot to take down the communist leader was revealed in a classified 1975 report that is part of the near-3,000 documents about the assassination of John F. Kennedy that were ordered to be released by President Donald Trump on Thursday.

The CIA has long been rumored to have planned a series of assassination attempts against Castro using elaborate means, from using exploding cigars to poisoned pills to putting thallium salt in his shoes. Castro's inner circle estimate that there were some 634 attempts to take his life.

But the document officially reveals the schemes that focused on Castro's love of skin diving, hoping that he would pick up the beach shell and trigger an explosive, and another that considered giving the revolutionary a contaminated diving suit.

"During this period there were also discussions about booby-trapping a spectacular seashell, which would be submerged in an area where Castro often skin dived," the file said.

The diving suit plot was so outlandish that it was to involve the use of fungi dust to make Castro unwell.

"The CIA plan was to dust the inside of the suit with a fungus producing madera foot, a disabling skin disease, and also contaminating it with tuberculosis bacilli in the breathing apparatus," the paper said.

Castro, who overthrew U.S.-backed Cuban leader Fulgencio Batista in 1959, died of natural causes in November 2016 aged 90, with power now centered in the hands of his brother Raul.

One of the world's longest-serving leaders, Castro managed to withstand numerous American plots, but some never materialized. One in particular included the hiring of a Mafioso in 1961 to smuggle lethal pills into Cuba and pay someone to slip them into Castro's drink, offering $150,000 for the job.

"The Phase I plans involved the preparation of poison botulism pills by the CIA, the delivery of those pills to organised crime figures who in turn were to get the pills delivered to contacts they had in Cuba, who in turn were to get the pills into the hands of someone who could place them in a beverage to be drunk by the Premier Castro," the documents read.

The Mafia boss in question, Chicago's Sam "Momo" Giancana, declined to be paid but received $11,000 in expenses for the job.

It has never been disclosed if the pills ever reached Cuba, but the plot was real. The pills were tested on guinea pigs first, and JFK's brother and then-Attorney General Robert F. Kennedy reacted angrily when he obtained knowledge of the plot.

"Never again take such steps without checking with the Department of Justice," he told the CIA.