Russian soldiers in Ukraine. Not Russian soldiers in (what he is claiming) as Russia.He's already claiming it and the weaponry is already killing Russian soldiers. Ukraine have also attacked Crimea and Russian Black sea fleet so, this basically changes nothing. I think the biggest worry is Russia mobilizing Ukrainians from the annexed teritory.
Putin is itching for a fight with NATO, what he refers to as the West. It is behind this whole mess. And because he is doing so badly conventionally, upping the stakes will be his reaction.