Cuba was an ally of the erstwhile USSR and received diplomatic and financial aid from the country. The then leader of the Soviet Union Nikita Khrushchev along with his advisors were apprehensive that the USA could invade the communist ruled Cuba in a bid to overthrow the Cuban president Fidel Castro. They decided to convert Cuba into a Russian base and thus, they placed nuclear missiles in that country in 1962. This act caused the doubling of the number of bases or cities in America that could be threatened by the USSR as the American mainland was now within firing range of the USSR missiles. Knowledge of the placement of missiles came to the Americans after three weeks. The then President of USA, John F. Kennedy along with his advisors were reluctant t initiate a full-scale nuclear war. But they wanted Russia to remove the missiles and nuclear weapons from Cuba. In retaliation of the missilie placements, American warships were ordered to intercept any soviet ships heading to Cuba as a warning to the USSR. An imminent clash was averted when the Soviet ships decided to turn back. This entire episode is known as the Cuban Missile Crisis.