"It's impossible to be optimistic at the moment. We're not in any position to be optimistic about the security situation and what is happening in the Crimea."
The crisis has had a huge knock-on effect on global stock markets, with Moscow's stock exchange plunging as much as 10% on Monday morning.
Russia's central bank raised its rate to 7% from 5.5% as the ruble hit an historic low against the dollar and the euro.