Russia hopes to claw back ground it lost in southern Kherson and Zaporizhzhya regions, he added, Ukraine's Ground Forces Commander Oleksandr Syrskyy has told Reuters.
Ukrainian troops, for their part, are staging smaller counter-attacks in what Syrskyy described as "active defence": keeping the enemy on its toes by seeking opportunities to strike while they look to regain the initiative.
He noted that Russian troops pressing were in multiple directions along the eastern front with the aim of wresting full control of the industrial Donbas region despite heavy losses in men and supplies ahead of the second anniversary of the invasion.
Engagements on both sides are on a smaller scale to conserve ammunition and men, he added, suggesting Russia has also learned to react and stem losses.