On October 22, President Kennedy appeared on television and announced the U-2 findings to an anxious public. Despite assurances from the Soviet government that the buildup was defensive in nature, he said, medium-range and intermediate-range ballistic missiles had been introduced into Cuba. He called for their withdrawal or elimination. As one measure to solve the crisis, he proclaimed a naval "quarantine" of Cuban ports to prevent the introduction of additional Soviet armaments. Kennedy also warned that further actions might be needed if the buildup of offensive weapons continued.
SIGINT collectors listened to the radio messages to and from the Soviet vessels on their way to Cuba. Would they turn around, or would they challenge the U.S. Navy "quarantine" that the president had imposed on Cuba? A cordon of U.S. Navy vessels awaited the Soviet cargo vessels in the Atlantic. Conflict between them, if it happened, carried with it the possibility of escalation into a wider war between the two superpowers.