WASHINGTON (Reuters) - U.S. President Barack Obama piled pressure on Russian President Vladimir Putin on Monday to force pro-Russian separatists in Ukraine to stop blocking an international investigation into the downing of a passenger jet last week.
In what has become a dramatic escalation in the worst East-West crisis since the Cold War, Obama denounced the Russian role in eastern Ukraine in some of his strongest language yet and pointedly appealed to Putin to cut ties with the separatists or risk greater international isolation.
