John F. Kennedy, Radio and Television Report to the American People on the Soviet Arms Buildup in Cuba Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/236392
The size of this undertaking makes clear that it has been planned for some months. Yet only last month, after I had made clear the distinction between any introduction of ground-to-ground missiles and the existence of defensive antiaircraft missiles, the Soviet Government publicly stated on September 11 that, and I quote, “the armaments and military equipment sent to Cuba are designed exclusively for defensive purposes,” that, and I quote the Soviet Government, “there is no need for the Soviet Government to shift its weapons . . . For a retaliatory blow to any other country, for instance Cuba,” and that, and I quote their government, “the Soviet Union has so powerful rockets to carry these nuclear warheads that there is no need to search for sites for them beyond the boundaries of the Soviet Union.” That statement was false.
Only last Thursday, as evidence of this rapid offensive buildup was already in my hand, Soviet Foreign Minister Gromyko told me in my office that he was instructed to make it clear once again, as he said his government had already done, that Soviet assistance to Cuba, and I quote, “pursued solely the purpose of contributing to the defense capabilities of Cuba,” that, and I quote him, “training by Soviet specialists of Cuban nationals in handling defensive armaments was by no means offensive, and if it were otherwise,” Mr. Gromyko went on, “the Soviet Government would never become involved in rendering such assistance.” That statement also was false.