West struggles with Russia's 'ambiguous warfare' tactics

Russian President Vladimir Putin chairs a meeting of the Security Council at the Kremlin in Moscow, November 20, 2014. REUTERS/Alexei Druzhinin/RIA Novosti/Kremlin

WASHINGTON (Reuters) - When Russians crossed the border to fight with rebels in eastern Ukraine earlier this year, Moscow said the soldiers had not been deployed but had gone on their own vacation time.

When Estonia was the victim of a cyber attack in 2007 and blamed Moscow, the Kremlin responded that it could not always control patriotic Russian hackers.