Stock futures fell after the U.S. issued a warning against Iran, leading to a 273-point drop in Dow Jones Industrial Average futures and S&P 500 futures. The Iran war has entered its fourth week, with President Donald Trump threatening to attack Iranian power plants if the Strait of Hormuz isn't reopened. Iran responded by threatening to target U.K. infrastructure, including energy and desalination facilities, if the U.,S. carried out its threat. The S&PA Global Flash U.