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 island. US officials attempted to use a Corona photoreconnaissance satellite to obtain coverage over reported Soviet military deployments, but imagery acquired over western Cuba by a Corona KH-4 mission on October 1 was heavily covered by clouds and haze and failed to provide any usable intelligence. At the end of September, Navy reconnaissance aircraft photographed the Soviet ship "Kasimov", with large crates on its deck the size and shape of Il-28 jet bomber fuselages. In September 1962, analysts from the Defense Intelligence Agency (DIA) noticed that Cuban surface-to-air missile sites were arranged in a pattern similar to those used by