President Obama speaks during a joint news conference with Philippine President Benigno Aquino III at Malacanang Palace in Manila, Philippines, on Monday. Obama said the U.S. and EU were planning new economic sanctions against Russia. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

Masked pro-Russian activists guard a barricade outside the regional state building seized by separatists in the eastern Ukrainian city of Donetsk Saturday. Pro-Russian forces holding a group of international observers have accused them of being "NATO spies." Alexander Khudoteply/AFP/Getty Images hide caption

itoggle caption Alexander Khudoteply/AFP/Getty Images

Armed pro-Russia activists stand outside the Ukrainian regional administration building in the eastern Ukrainian town of Slovyansk on April 14. Evgeniy Maloletka/AP hide caption

itoggle caption Evgeniy Maloletka/AP

U.S. journalist Simon Ostrovsky in Moscow in 2004. He was reportedly released on Thursday after being held briefly by pro-Russian separatists in eastern Ukraine. Alexander Nemenov/AFP/Getty Images hide caption

itoggle caption Alexander Nemenov/AFP/Getty Images

A masked guard holds a young boy at a barricade outside a building being held by pro-Russia forces in Donetsk, Ukraine. Eleanor Beadsley/NPR hide caption

itoggle caption Eleanor Beadsley/NPR