Demonstrators burn a poster of U.S. President Barack Obama and outgoing Israeli Prime Minister Ehud Olmert, front, and an anti-U.S. poster depicting U.S. Presidents George H.W. Bush, Barack Obama, George Bush, Bill Clinton and Jimmy Carter, out side of the former U.S. Embassy during a demonstration on the anniversary of freezing Iran-U.S. diplomatic ties, in Tehran, on Thursday April, 9, 2009. The United States and Iran have not had diplomatic relations since the 1979 Islamic Revolution and subsequent hostage taking at the U.S. Embassy in Tehran.