It's the Ukrainian nationalists. They were accepted as a division in the Ukrainian and now appear to be ignoring the Ukrainian military orders all together. It's why the Russian army is trying so hard to not only spare civilians, but also spare any Ukraine military who wish to give up arms. It's the nationalists doing all the damage. It's also why they (Russia and Ukraine) keep agreeing on establishing corridors to offer humanitarian aid and evacuate, but when they do, the nationalists start attacking and the people can't get out.