MOSCOW, RUSSIA - DECEMBER 21: L-R: Armenian President Serge Sargsyan, Belarussian President Alexander Lukashenko, Kazakh President Nursultan Nazarbayev, Russian President Vladimir Putin, Kyrgyz President Almazbek Atambayev, Tajik President Emomali Rakhmon, CSTO Secretary Nikolai Borduzha pose for a photo duringh the Summit of Collective Security Treaty Organisation (CSTO) in Grand Kremlin Palace December 21, 2015 in Moscow, Russia. Leaders of post-Soviet states - Belarus, Armenia, Kazakhstan, Tajikistan, Kyrgyzstan and Russia have gathered in Moscow for the CSTO Summit. (Photo by Sasha Mordovets/Getty Images)
