Which event was the first to cause tension between the Soviet Union and President Kennedy?

It was the Cuban Missile Crisis. This was a 13 day conflict between the United States and the Soviet Union that began on October 16 to October 28, 1962. This began when Russians installed ballistic missiles in Cuba in response to U. S. missiles in Italy and Turkey. It would have escalated into full-scale nuclear conflict. In response, the U. S. set up a blockade to prevent missiles from deployed in Cuba. After a long stand-off, both countries held negotiations wherein the Russians agreed to remove their missiles from Cuba and the Americans removed their missiles from Turkey and Italy.