Only at a very heavy cost of troops and equipment and the Russian army has nearly exhausted its reserves of troops and arms, leaving them vulnerable to a counterattack when the incoming military equipment from the west is fully integrated into the Ukrainian armed forces.
Later reports by police confirmed that the shooter was a long-time mental patient who'd had several detainments in psychiatric facilities and was known for frequently going off his meds. The right wingers in the US are beside themselves with joy.
PT Barnum was truly a prophet.