In his 1987 Reflections on the Cuban Missile Crisis, Raymond L. Garthoff wrote that, “By November 8 the United States had begun perceptibly to stiffen its insistence” on various issues not resolved by the October 28 Kennedy-Khrushchev agreement, “including what the Soviets could only see as an effort to backpedal on what was, for them, the key question remaining: American assurances not to attack Cuba. On that date, a Cuban covert action sabotage team dispatched from the United States successfully blew up a Cuban industrial facility.” Garthoff said that sabotage had been planned before the October 28 agreement and was beyond recall when the Kennedy administration realized it was still in progress, However, “To the Soviets, this was probably seen as a subtle American reminder of its ability to harass and attempt to subvert the Castro regime.”[50] Chomsky says this sabotage killed “four hundred workers, according to a Cuban government letter to the UN secretary general.[51]