A US plot to pay Cubans for killing Cuban officials and Communist sympathizers was revealed in a batch of CIA files released on Thursday.

Only $0.02 was offered up for the killing of Prime Minister Fidel Castro, an offer that was meant "to denigrate" the revolutionary leader in the eyes of the Cuban people.

The bounty operation never happened, but it didn't prevent the US government from trying to oust Castro, unsuccessfully, for decades.

President Donald Trump approved the release of about 2,800 top secret documents on Thursday related to the federal investigation into the assassination of former President John F. Kennedy in 1963.

One file exposed a plot crafted by senior leaders in the Kennedy Administration encouraging Cubans to kill government agents for financial rewards.

The bounties for targeting Communist informers, cell leaders, department heads, foreign supporters, and government officials ranged from $5,000 to as much as $100,000. The plan, according to the newly released file, was to drop leaflets from the air in Cuba advertising the rewards.

A meager $0.02 was offered for the killing of Fidel Castro, then Cuba's prime minister.

In 1975, Edward Lansdale, a prominent CIA intelligence official, testified to the Senate that the pocket-change offering for the Cuban leader was meant "to denigrate ... Castro in the eyes of the Cuban population." Lansdale was known for leading counter-insurgency missions in developing countries, especially in Vietnam and the Philippines.

The recently released JFK file goes on to say that once the plan was implemented, US agents would "kidnap known [Communist] party members thereby instilling confidence in the operation among the Cuban populace and apprehension among the Cuban hierarchy."

The kill-for-pay plan — dubbed "Operation Bounty" — never took hold. Lansdale said he "tabled" the concept because he didn't think "it was something that should be seriously undertaken or supported further."

It's unclear why exactly he thought the plan should have been scrapped. The CIA had, on numerous occasions, attempted to assassinate Castro and overthrow his Communist government.