Pavlicek informs Prague that Cuban anti-aircraft forces fended off and shot down a group of U.S. jet bombers, which were assumed to be on a mission to examine the missile bases in Cuba. He also intercepted a message from Washington that if Cuba does not leave a free zone for American personnel to land and inspect the bases, there will be "further action." The bases are not to be dismantled, and an invasion by the United States is to be anticipated.

Further reports from Pavlicek indicate despite soft rhetoric from the United States indicating a willing to negotiate, aggressive preparations against Cuba continued. In particular, there was a large reinforcement of air force bases in Florida and Key West, as well as an announcement of increased intensity of air reconnaissance over Cuba. By the time of this message, there already have been exchanges between Cuban anti-aircraft guns and U-2 recon planes. However, there are no significant measures observed among military installations in Europe, with Czechoslovak troops maintaining maximum combat readiness. Very few instances of insubordination and dissent are found.

The cable concerns a conversation between Vrana and Pinner the night before, about Castro's conviction of an impending invasion of Cuba by the United States and associated mercenaries. Prague is told if that event comes to pass, all classified documents in the embassy will be burned. Emergency measures are being prepared, and tensions are evidently high.

The cable states Cuba has alerted its armed forces to maximum combat readiness. Cuba's government had already taken the precautions of arresting known counterrevolutionaries in all aspects of society, with all important factors monitored. General aura of the country is one of tenseness, but the people continue about their lives as normal. There is a sense of strong revolutionary unity in the wake of this blockade, especially after a speech given by Castro. Cable concludes with a message that the first Soviet ship arrived on the basis of not carrying any military hardware.

This cable sent to Prague confirms the decision by President John F. Kennedy to blockade Cuba, based on talks between Cuban Foreign Minister Raul Roa and Soviet Ambassador to Cuba Aleksandr Alekseev. Despite no orders for the American warships to stop Soviet ships, Alekseev was preparing in anticipation for "dangerous provocations." Cuba canceled all PanAm flights, while at the same time allowing Czech and Soviet flights to proceed.

Czechoslovak Intelligence reports on a possible assassination plot against Castro and a possible coup against the Revolutionary Government in Havana. The document details the plot being planned by individuals in Havana including smuggling explosives into a public celebration for 1 May. Microfilms containing information on the plot including the organizers and place of action. It is obvious from this correspondence that the planned assassination and coup against Castro are part of the Bay of Pigs Invasion.

The report details a meeting between Deputy Foreign Minister Hajek with Cuban Foreign Minister Raul Roa. After a dinner banquet which is attended by all members of the Cuban foreign ministry and the Czechoslovak embassy, Hajek and Roa pay a visit to Ernesto "Che" Guevara, Chairman of the Cuban National Bank. Conversations ranged from Cuba's international status to ways of thwarting American aggression. It is noted that Guevara was highly paranoid of an American attack on Cuba.