Answer:
They were afraid that the US would try to invade Cuba, since previously the US government had supported the invasion of the Bay of Pigs.
Explanation:
The invasion of the Bay of Pigs, also known as the Bay of Pigs invasion or the Battle of Girón, was a military operation in which troops of Cuban exiles, supported by the United States invaded Cuba in April 1961, to try to create a beachhead , form a provisional government and seek the support of the Organization of American States and the recognition of the international community. The action ended in failure in less than 65 hours. It was completely crushed by the Militias and the Revolutionary Armed Forces (FAR) of Cuba. More than a hundred invading soldiers died, and the Cubans captured another 1200, along with important war material.