UKRAINE-RUSSIA-POLITICS-CRISIS-MILITARY

Russian ships block the Slavutych Ukrainian navy ship moored in Sevastopol bay on March 20, 2014. European leaders prepared on March 20 to debate biting economic sanctions against Russia for its annexation of Crimea as Ukraine tore up key ties with the Kremlin and drew up plans to evacuate its nationals from the rebel peninsula. The European Union is under intense pressure to find a credible response to an explosive security crisis on the 28-nation bloc's eastern frontier that NATO chief Anders Fogh Rasmussen on Wednesday called "the gravest threat to European security and stability since the end of the Cold War.AFP PHOTO/ VIKTOR DRACHEV (Photo by VIKTOR DRACHEV / AFP) (Photo by VIKTOR DRACHEV/AFP via Getty Images)