Cuban Missile Crisis established a naval blockade on October 22 to prevent further missiles from reaching Cuba; Oval Office tapes during the crisis revealed that Kennedy had also put the blockade in place as an attempt to provoke Soviet-backed forces in Berlin as well. The US announced it would not permit offensive weapons to be delivered to Cuba and demanded that the weapons already in Cuba be dismantled and returned to the Soviet Union. After several days of tense negotiations, an agreement was reached between US President John F. Kennedy and Khrushchev. Publicly, the Soviets would dismantle their offensive weapons in Cuba and
Cuban Missile Crisis fire only on groups of two or more. At 6:00 am EDT on October 27, the CIA delivered a memo reporting that three of the four missile sites at San Cristobal and the two sites at Sagua la Grande appeared to be fully operational. It also noted that the Cuban military continued to organize for action but was under order not to initiate action unless attacked. At 9:00 am EDT on October 27, Radio Moscow began broadcasting a message from Khrushchev. Contrary to the letter of the night before, the message offered a new trade: the missiles on Cuba would