Iran’s supreme leader Ayatollah Ali Khamenei warned Friday the U.S. should prepare for a “hard slap” if it dares challenge Tehran, after President Donald Trump warned of possible military action against the Islamic republic. “The Americans should know threats will get them nowhere when confronting Iran,” Khamenei said in his live annual televised speech marking Nowruz, the Persian New Year. AFP reports he said Americans “and others should know that if they do anything malign to the Iranian nation, they will get a hard slap.” The warning echoes a long standing Iranian opposition to everything the U.S. is involved in...