What led President John F. Kennedy to blame Soviet premier Nikita Khrushchev for causing a threat to world peace?

He blamed him for spreading communism (he did) and for setting up nuclear missile silos all over the globe (he did, but so did we). He blamed lots of things on him (most true, but we did the same things).

Kennedy blamed Khrushchev for causing a threat to world peace after the United States found Soviet missiles stationed in Cuba.

The US government felt that this was a direct threat to the United States, as Cuba was only 90 miles away from the US. This would meant that the Soviet Union could attack the US in mere minutes. This confrontation between the two men over the missiles discovered in Cuba would become known as the Cuban Missile Crisis. Over the course of 13 days, the US and Soviet Union came extremely close to all out nuclear warfare. However, the US and Soviet government eventually struck a deal in which the Soviet's removed their missiles from Cuba while the US removed their missiles from Turkey.