NEW YORK - Cuban revolutionary leader Fidel Castro has urged the United States and North Korea to back off from confrontation, warning that if a war broke out on the Korean peninsula it would affect over 70 per cent of the planet.As the nuclear stand-off continues, Castro, the 86-year-old Communist icon and former president denounced “the gravity of such an incredible and absurd event” in the region which is home to five out of seven billion people living on Earth. A war in the region would result in “a terrible slaughter of people” in both North and South Korea and neither of them would benefit from it, Fidel Castro wrote in an article in Cuban Granma newspaper, which was distributed in New York by the Cuban Mission to the United Nations.Castro said he believes that the “duty” to avoid the violence is also in the hands of the White House and the American people. In case of a war, President Barack Obama would turn into “the most ominous leader” in the history of the country, Castro added. In the Cuban leader’s view, the current situation on the Korean Peninsula poses the most serious threat of a nuclear war since the Cuban Missile Crisis in 1962 - a two-week confrontation between the Soviet Union and the United States over placing nuclear missiles on the Caribbean island.