WASHINGTON/DUBAI (Reuters) – U.S. President Donald Trump threatened on Tuesday to obliterate parts of Iran if it attacked “anything American,” in a new war of words with Iran which condemned fresh U.S. sanctions on Tehran as “mentally retarded.” But Trump later left the door open for talks, saying that Iran should speak to the United States “peaceably” to ease tensions and potentially lift U.S. economic sanctions. The U.S. president on Monday signed an executive order imposing additional, largely symbolic, sanctions against Iranian Supreme Leader Ayatollah Ali Khamenei and other senior figures, with punitive measures against Foreign Minister Mohammad Javad Zarif expected later this week. Iran shot down a U.S. drone last week and Trump said he had called off a retaliatory air strike with minutes to spare, saying too many people would have been killed. It would have been the first time the United States had bombed the Islamic Republic in four decades of mutual hostility. Nick Bit: Tell me Mr. President are you hearing laughter?