Stocks slumped and oil prices soared on Thursday after President Donald Trump vowed the US will continue to attack Iran and failed to offer a clear timetable for ending the conflict in the Middle East.The S&P 500 fell 1.1 per cent, with three out of every four stocks in the benchmark index losing ground. The Dow Jones Industrial Average shed 545 points, or 1.2 per cent, as of 9.52am Eastern. The Nasdaq composite fell 1.6 per cent. Major indexes throughout Europe and Asia also fell.The broad...