At this point denying that Russian forces are involved in the fighting in Ukraine is pointless. There is so much evidence for it so I don't think even Russia thinks people are buying it. They might be doing it for their domestic propaganda or just buying time for something.
Besides the amount of firepower the separatists have would be utterly impossible if it wasn't being shipped from Russia.
http://www.kyivpost.com/content/ukra...rs-362535.html
Ukrainians seem to be fighting with attitude.