German chancellor Angela Merkel and Ukraine prime minister Arseniy Yatsenyuk at an emergency summit in Brussels. (Image by Unknown Owner) Details DMCA | Barack Obama ramped up pressure on Russian president Vladimir Putin on Thursday by imposing visa restrictions on officials for "threatening the sovereignty of Ukraine and signing an executive order enabling further sanctions against Moscow. The White House said the measures were a response to Russia s "ongoing violation of Ukraine s sovereignty and territorial integrity , a reference to its intervention in the southern peninsula of Crimea. |