Russia's Plan C
"Here we come to the big choices the Russian military must make. Artillery can be used, brutally, as an instrument of urban warfare, to demoralise the defenders, to remove defensive positions and create pathways for an offence. But we know, from Stalingrad to Grozny, that defenders can fight amongst the rubble. Even at that desperate stage, urban settings remain a challenge for invading force. Units can get lost and isolated, caught in city streets, with reliable intelligence difficult to acquire. If Russian commanders want to keep their casualties down this is an uncomfortable prospect.
Furthermore, to emphasise an early point, and as we have seen in areas where Russians have moved in, presence is not the same as control. There are numerous images now of Russian troops being confronted by large crowds of angry, unarmed residents and unsure what to do. It is one thing to kill civilians from afar with artillery and missile strikes, but another to have to look ordinary people in the eye, who could be your relatives, in a street similar to your home town, and start to shoot them out of the way. Somehow if they wish to hold what they have taken, the occupying forces will have to introduce the numbers able to impose curfews and deal with protestors, while protecting themselves from ambushes.
The alternative might be to mount sieges. The population can be forced to spend their time in bunkers, while cities loses power, food and medicines becomes scarce, and the situation becomes progressively more distressing. This may end up being, by default, Plan C, especially if Russians continue to struggle with efforts to get more than footholds in the major cities. "
more in the analysis by Lawrence Freedman