A Ukrainian soldier stands guard near an APC at a checkpoint outside the city of Slaviansk

A Ukrainian soldier stands guard near an armored personnel carrier (APC) at a checkpoint outside the city of Slaviansk April 27, 2014. The leader of separatist rebels holding a group of international observers in the Ukrainian city of Slaviansk said he was scheduled on Sunday to meet a delegation of mediators who were on their way to negotiate the observers’ release. REUTERS/Gleb Garanich (UKRAINE — Tags: MILITARY POLITICS CIVIL UNREST)