"The United States and the 28-member European Union (EU) have pursued similar policies in response to the crisis in Ukraine. Both have provided additional financial aid to bolster Ukraine's political transition, condemned Russia's annexation of Crimea, and called for Russia to end its support of separatists in eastern and southern Ukraine. The United States and the EU have taken steps to isolate Russia diplomatically and imposed targeted economic sanctions in an effort to change Moscow's behavior and bring an end to the conflict. […] Initially, some U.S.-EU differences were evident as the two sides grappled with how best to respond to Russia's actions. EU officials were more wary than their U.S. counterparts of sanctioning Russia because of significant EU-Russian trade and investment ties and the dependence of some EU countries on Russian oil and gas supplies […]."
CRS Insight, IN10129