From the Background: "The United States and the 28-member European Union (EU) have pursued similar policies in response to the conflict in Ukraine. (For background, see CRS Report RL33460, Ukraine: Current Issues and U.S. Policy.) Both have provided financial aid to bolster Ukraine's political transition and economy, condemned Russia's annexation of Crimea, and called for Russia to end its support of separatists in eastern Ukraine. They have also urged the full implementation of the September 2014 and February 2015 ceasefire agreements. Following the annexation of Crimea in March 2014, the EU and the United States adopted a series of visa bans and asset freezes on several dozen Russian and Ukrainian individuals and entities. Despite the subsequent conflict in eastern Ukraine, however, many European officials were wary initially of imposing stronger sanctions that they feared might isolate and provoke Russia and jeopardize trade and investment relations; some EU countries highly dependent on Russian oil and gas supplies also worried about endangering energy sector ties. U.S. officials insisted publicly that they would prefer to escalate sanctions on Russia in cooperation with the EU, but many, including some Members of Congress, were frustrated with the reluctance of certain EU countries to agree to tougher sanctions. In the absence of parallel EU action, President Obama announced U.S. sanctions on select Russian financial, energy, and defense companies on July 16, 2014 (see CRS Report IN10048, U.S. Sanctions on Russia in Response to Events in Ukraine)."
CRS Insight, IN10129
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html