The answer is the bay of pigs invasion
The U.S government worried about the relationship between Castro and the leader of uni Soviet , Nikita Khrushchev ( we got a cold war with the uni Soviet Baack then)
So, the CIA devised a plan to train Cuban Exiles for the invasion of their homeland through Bay of Pigs.
The Invasion later became a disaster as the American army was destroyed and more than 1200 of them were surrendered.
