Russia is preparing for counteroffensives in the east and south of Ukraine. To this end, they are said to have set up "killing zones" on a massive scale.
There are staggered defense posts from the Zaporizhzhia region up to and including the Donetsk region. Russian military leaders, in all likelihood, assess these areas as the most "dangerous" terrains in terms of Ukrainian attacks.. Russia has apparently built massive defensive lines in southeastern Ukraine to shield the occupied territories against Ukrainian offensives.