Talk of the Russians moving back from Kiev should be treated with the upmost scepticism. Putin is not only deranged he is a known liar, having said once he had no plans to invade Ukraine at all.
Does everyone not see what I see when I look at those maps every night on TV? It is sad to say but Mariupol is doomed to eventually fall & then that map will show a complete red, horseshoe-shape open to the west surrounding the East side of the country, from Crimea along the new corridor to the Donbas & along the top to Kiev. Then there will be a full pincer movement driving out the troops in the centre, back to Kiev.
The plan will then be to split the country in two with Kiev & a new puppet government forming East Ukraine & the West Ukraine will have Lvov as it's capitol.
That is the plan & I'm sure it will happen, unless that is, someone steps up to the plate & blows Putin's effing brains out.