Putin today called it an 'illegal act of aggression' and the US was also branded 'a partner of ISIS' by al-Assad's spokesman
Yup, Putin is loving Trump.
I have to say that they are not jumping up and down as much as I thought they would, although they have undertaken to bolster Syrian air defences. I'm just not sure that Russia really wants a major confrontation in Syria, I don't mean just in military terms, but in general. Yes side with Assad, but not too much ? It's just not worth it, even if the rebels were out of the way there would be so many other issues, ISIL, Kurds, Israel and who knows what else. Plus of course there would be Assad himself to deal with.