President Dmitry Medvedev (center, foreground) to attend the Collective Security Treaty Organization summit with enlarged attendance of delegations, December 20, 2011. Left, background: Kazakhstan President Nursulatan Nazarbayev. Right, background: Belarus President Alexander Lukashenko. Left, background: Tadjikistan President Emomali Rakhmon. Right, background: Uzbekistan President Islam Karimov.