NEW: Qatar’s prime minister arrives in Tehran as the push to de-escalate the war runs headfirst into a warning from President Trump: the U.S. will keep fighting

NEW: Qatar’s prime minister arrives in Tehran as the push to de-escalate the war runs headfirst into a warning from President Trump: the U.S. will keep fighting as long as necessary. Tensions remain high in the Strait of Hormuz, where Iran says the critical waterway will stay closed until Washingto…