President Joe Biden said Thursday that US and British forces had launched air strikes against Iran-backed Houthi rebels in Yemen in “defensive action” after attacks on shipping in the Red Sea. In a statement, Biden said he “will not hesitate” to order further military action if needed. Air strikes hit a number of cities in Yemen, where the Houthis control a swathe of territory, a Houthi source and witnesses said. The strikes involved fighter jets and Tomahawk missiles, several US media said. “Today, at my direction, US military forces — together with the United Kingdom and with support from A…