MOSCOW (REUTERS) - Russia has prepared a classified document setting out actions it would take if Western nations impose further sanctions on Moscow over its involvement in Ukraine, President Vladimir Putin's top economic aide said on Friday.

"I can say that strategy or no strategy, there is a tactic, it has been worked out, it is in the form of a document - a document that is closed, for obvious reasons," Andrei Belousov told state-run Rossiya-24 television.