KIEV, UKRAINE - MARCH 19: Barricades are viewed in Maidan Square, the site of months of often violent protest that led to the ouster of former Ukrainian  president Viktor Yanukovich on March 19, 2014 in Kiev, Ukraine. Tensions in Crimea continue as Russian President Vladimir Putin announced yesterday the annexation of Crimea. Voters in the semiautonomous territory approved a quickly called referendum on separating from Ukraine.  (Photo by Spencer Platt/Getty Images)