U.S. Secretary of State John Kerry is urging Russia to support efforts to free military observers from the Organization for Security and Cooperation in Europe (OSCE) being held by pro-Russian forces in Ukraine.
Kerry also told Russian Foreign Minister Sergey Lavrov in a call April 26 that the United States is concerned that Moscow's actions are "undermining stability, security and unity" in Ukraine.
For his part, Lavrov urged Kerry in the same call on April 26 to use his influence to win the release of pro-Russian separatist leaders who have been detained by authorities in Kyiv.
Pro-Russian separatists in the eastern Ukrainian city of Slaviansk say they are ready to exchange the OSCEl observers they call "spies" for fellow rebels who are in custody of in Kyiv.