Russian President Vladimir Putin, second right, looks on as Crimean leaders, Speaker of Crimean legislature Vladimir Konstantinov, second left, Crimean Premier Sergei Aksyonov, left, and Sevastopol mayor Alexei Chalyi, right, sign a treaty for Crimea to join Russia in the Kremlin in Moscow, Tuesday, March 18, 2014. President Vladimir Putin on Tuesday signed a treaty to incorporate Crimea into Russia. [Photo/icpress.cn]