(5-4-14) Putin has called for an emergency UN Security Council meeting to discuss "the serious escalation of violence in Ukraine" and there's been a lot of speculation on what his intent is -- since obviously he's not going to get anything he wants out of the UN in terms of asking for protection of Russian nationals in eastern Ukraine. And of course the UN is not going to put in some force for monitoring or protecting the Russians.
It isn't really a PR move, but a prelude or an excuse since he knows that the UN is very slow to insert UN forces. It's a go-ahead move, which gives him an excuse to insert Russian forces because he can say that he had to do it since the UN wouldn't act. This is actually a smart move on his part. You go to the body that is the slowest to react, i.e. the United Nations. They can't even keep so-called peace keeping forces in a country for twelve months. But it does provide a pretty good diplomatic and political cover for him to say -- oh the UN won�t protect Russian nationals.