By Anna Yukhananov and Steve Holland WASHINGTON Wed Jul 16, 2014 9:26pm EDT (Reuters) – President Barack Obama imposed the biggest package of U.S. economic sanctions yet on Russia on Wednesday, hitting Russia’s largest oil producer Rosneft and other energy, financial and defense firms, with what he called significant but targeted penalties. Obama’s latest round of sanctions came after close consultations with European leaders, who announced a less-ambitious package. The ultimate impact of the U.S. […]