The US military is preparing to put up to three aircraft carriers and their accompanying warships into the Middle East, potentially creating a force of nearly 20,000 troops and as many as 150 fighter jets, as President Donald Trump weighs whether to resume large-scale strikes against Iran. The planning, reported by US officials, is designed to give Trump and US commanders greater flexibility in the coming weeks. If all three carrier strike groups move into the region, they would bring together a substantial concentration of combat aircraft, missile-capable destroyers and thousands of sailors and Marines.